UNIVERSITY OF CALIFORNIA PUBLICATIONS 

COLLEGE OF AGRICULTURE 
AGRICULTURAL EXPERIMENT STATION 

BERKELEY, CALIFORNIA 



SOME MEASURING DEVICES USED 

IN THE DELIVERY OF 

IRRIGATION WATER 



BY 

CALIFORNIA AGENTS OF IRRIGATION INVESTIGATIONS, OFFICE OF 

EXPERIMENT STATIONS, U. S. DEPARTMENT 

OF AGRICULTURE 

( Based on work done under co-operative agreement between the Office of Experiment Stations and 

the State Engineering Department of California and between the Office of Experiment Stations 

and the University of California Agricultural Experiment Station.) 



BULLETIN No. 247 

Berkeley, Cal., January, 1915 



UNIVERSITY OF CALIFORNIA PRESS 

BERKELEY 

1915 



Benjamin Ide Wheeler, President of the University. 

EXPEKIMENT STATION STAFF 

HEADS OF DIVISIONS 

Thomas Forsyth Hunt, Director. 

Eugene W. Hilgard, Agricultural Chemistry (Emeritus). 

Edward J. Wickson, Horticulture. 

Herbert J. Webber, Director Citrus Experiment Station; Plant Breeding. 

Hubert E. Van Norman, Vice-Director; Dairy Management. 

AVilliam A. Setchell, Botany. 

Meyer E. Jaffa, Nutrition. 

Robert H. Loughridge, Soil Chemistry and Physics (Emeritus). 

Charles W. Woodworth, Entomology. 

Ealph E. Smith, Plant Pathology.. 

J. Eliot Coit, Citriculture. 

John W. Gilmore, Agronomy. 

Charles F. Shaw, Soil Technology. 

John W. Gregg, Landscape Gardening and Floriculture. 

Frederic T. Bioletti, Viticulture and Enology. 

Warren T. Clarke, Agricultural Extension. 

John S. Burd, Agricultural Chemistry. 

Charles B. Lipman, Soil Chemistry and Bacteriology. 

Clarence M. Harog, Veterinary Science and Bacteriology. 

Ernest B. Babcock, Genetics. 

Gordon H. True, Animal Husbandry. 

James T. Barrett, Plant Pathology. 

Arnold V. Stubenrauch, Pomology. 

Walter Mulford, Forest^. 

W t illiam G. Hummel, Agricultural Education. 

Frank Adams, Irrigation Practice. 

David N. Morgan, Assistant to the Director. 

Mrs. D. L. Bunnell Librarian. 

IRRIGATION PRACTICE 

(In co-operation with Office of Experiment Stations, U. S. Department of Agriculture, and 

State Engineering Department of California) 

Frank Adams. S. H. Beckett. 

O. W. Israelsen. 

Samuel Fortier, Chief of Irrigation Investigations, Office of Experiment Stations. 
W. F. McClure, State Engineer of California. 



Digitized by the Internet Archive 

in 2012 with funding from 

University of California, Davis Libraries 



http://www.archive.org/details/somemeasuringdev247unit 



CONTENTS 

PAGE 
Introduction 113 

Units of Water Measurement 116 

The Davis Field Laboratory 117 

Measuring Devices for Underground Distribution Systems 119 

Azusa Hydrant 119 

Gage Hydrant 121 

Kiverside Box 123 

Foote Inch Box 124 

Weirs , 126 

Cipolletti Weir 128 

Weir Without End Contractions 139 

Submerged Orifices 146 

Submerged Orifices with Fixed Dimensions 147 

Submerged Orifice Headgates ......" 153 

Mechanical Devices that Measure and Register the Total Flow 156 

Dethridge Meter 156 

Grant-Michell Meter 160 

Hill Meter : 161 

Hanna Meter ...:. 163 

Water Registers 164 

Current Meters 165 

Appendix — Data and Discussion of Tests of Measuring Devices 166 



Tables 

Table 1. Discharge of Cipolletti Weirs, 12 to 24 inches long 131 

Table 2. Discharge of Cipolletti Weirs, 3 to 5 feet long 135 

Table 3. Discharge of Weirs Without End Contractions per foot of length .. 140 

Table 4. Discharge of Submerged Rectangular Orifices 150 

Table 5. Coefficients to be Applied to Discharges Given in Table 4 when 

Orifice Suppressed - 152 



[111] 



Illustrations 

PAGE 

Plate 1. Davis Field Laboratory of Irrigation Measuring Devices ..frontispiece 

Figure 1. Eeinforced Concrete Reservoir, Davis Field Laboratory 117 

Figure 2. Concrete Standardizing Box, Davis Field Laboratory 118 

Figure 3. Drawing of Azusa Hydrant 120 

Figure 4. Photograph of Azusa Hydrant from Above 121 

Figure 5. Drawing of Gage Hydrant 122 

Figure 6. Photograph of Gage Hydrant 122 

Figure 7. Drawing of Riverside Measuring Box 123 

Figure S. Photograph of Riverside Measuring Box 123 

Figure 9. Drawing of Foote Inch Box 125 

Figure 10. Photograph of Foote Inch Box 126 

Figure 11. Measuring Water with a Small Wooden Cipolletti Weir 127 

Figure 12. Drawing of Cipolletti Weir and Weir Box 128 

Figure 13. Photographs of Cipolletti Weir and Hanna Meter 129 

Figure 14. Photograph of Weir Without End Contractions 140 

Figure 15. Drawing of Submerged Orifice Used by U. S. Reclamation 

Service 147 

Figure 16. Photograph of Submerged Orifice Used by U. S. Reclamation 

Service 148 

Figure 17. Drawing of Submerged Orifice Headgate 153 

Figure 18. Photograph of Submerged Orifice Headgate 154 

Figure 19. Drawing of Dethridge Meter 157 

Figure 20. Photograph of Dethridge Meter 158 

Figure 21. Plan an Elevation of Installation of Grant-Michell Meter 160 

Figure 22. Photograph of Installation oi Grant-Michell Meter 161 

Figure 23. Sectional Elevation of Installation of 12-inch Hill Meter 162 

Figure 24. Photograph of Installation of 12-inch Hill Meter 162 

Figure 25. Photograph of Hanna Meter 163 

Figure 26. Photograph of a Water Register 164 

Figure 27. Photograph of Current Meter and Equipment 165 



[112] 



SOME MEASURING DEVICES USED IN THE 
DELIVERY OF IRRIGATION WATER 

BY* 

CALIFORNIA AGENTS OF IRRIGATION INVESTIGATIONS, OFFICE OF 

EXPERIMENT STATIONS, U. S. DEPARTMENT 

OF AGRICULTURE 



INTRODUCTION 

The public and private advantages attending the measurement of 
individual deliveries of irrigation water have for many years been 
appreciated in the older irrigated countries and in some portions of 
the western United States where irrigation water has had a high sale 
value. Now the rapidly increasing utilization of the available water 
supplies and the better understanding of the principles underlying the 
wise making of rates to be charged for irrigation water are causing 
these advantages to be better understood in every irrigated section of 
the West. Citing only California as an illustration of this, it needs 
only to be said that while, outside of the southern citrus sections, ap- 
pliances for measuring water deliveries were seldom considered in 
the design of irrigation systems ten or fifteen years ago, today no 
competent California irrigation engineer laying out an irrigation 
project would fail to give due consideration to necessary means for 

* The installation of the measuring devices described in this bulletin has 
been carried out chiefly by S. H. Beckett and R. D. Robertson, irrigation engi- 
neers, assisted by Roy Wray. The tests of the devices have been made under 
the immediate direction of S. T. Harding, irrigation engineer, in charge of 
irrigation investigations in Montana, temporarily on duty in California, who 
has also prepared the reports of the tests printed in the appendix. The weir 
tables included have been prepared by Wells A. Hutchins. The drawings and 
diagrams have been prepared by Stephen C. Whipple, scientific assistant. Mr. 
F. L. Bixby, irrigation engineer, in charge of irrigation investigations in New 
Mexico, temporarily on duty in California, assisted in designing the general 
plan of installation. The full study has been planned and, in general, super- 
vised, and the data have been arranged for publication by Frank Adams, Irriga- 
tion Manager. 

The installation of the Davis field laboratory and the testing of the devices 
have been jointly paid for from funds contributed by the State Engineering 
Department of California, the Office of Experiment Stations of the United 
States Department of Agriculture, and the California Agricultural Experiment 
Station. Co-operation with the State Engineering Department of California 
has been effected through agreement between that Department and the Office 
of Experiment Stations, the irrigation investigations at Davis having formerly 
been carried on by those two agencies without financial aid from the California 
Agricultural Experiment Station. 

[113] 



114 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 

measuring the water supplied to irrigators. Furthermore, the recent 
giving to one central public authority the power to fix rates charged 
for irrigation water by California public utilities has made a more 
general understanding of practicable means of measuring irrigation 
deliveries at least exceedingly desirable. 

The measurement of irrigation water, while theoretically simple, is 
rendered quite perplexing in practice because of the varying con- 
ditions almost any irrigation measuring device is required to meet. 
While extreme accuracy is not expected and thus far is almost never 
reached, measurements within, say, from two to five per cent of correct 
are reasonable to expect, and no device can be considered very satis- 
factory that does not accomplish such a result. Sometimes, and 
especially in the flatter valleys, irrigation ditches are but very little 
higher than the land to be watered, making measurement over a weir 
or other device requiring a free over-fall of the water impossible. In 
such cases some form of the submerged orifice (p. 146) or some kind 
of mechanical registering meter (pp. 156-164^ must be used. With 
almost any one of these, silt or debris carried in the water, as well as 
temporary changes in the canal or ditch above or below the measuring 
point (as from checking up the water to get it on to the higher land) 
sufficiently change conditions to alter results and to impair the 
accuracy of measurements if they are not taken account of. An 
additional element of difficulty is found in the fluctuations in flow 
that almost invariably occur on every system, the same device some- 
times being required to measure less and sometimes more than the 
quantity it is best suited to take account of. 

Besides measuring water with reasonable accuracy, under some- 
times widely varying conditions, a satisfactory device for taking 
account of farm water deliveries must be extremely simple in design, 
and be made of materials that are available and inexpensive. It 
should at least in part be susceptible of construction by the farmer to 
be served, and to be widely used, should not cost above, say, from 
twenty-five to fifty dollars. Where all of the farmers under one 
lateral receive the same flow of water in rotation, each retaining it 
for a length of time proportional to his interest in the system or the 
number of acres he irrigates, a device that both measures the rate of 
the flow and holds that flow constant is the ideal to be sought for. 
While there are few devices in use that hold the flow of water con- 
stant, reasonably satisfactory results are obtained under the rotation 
plan by measuring or gauging the turnout with sufficient frequency 
to enable its being held about uniform. Where rotation on laterals is 
not feasible, or where independent individual deliveries are preferred, 



Bulletin 247 IRRIGATION MEASURING DEVICES 115 

the measuring device, to be fully satisfactory, should register the total 
amount of water passing rather than the rate of the flow. While this 
result can be accomplished by using a water register (Fig. 26) in con- 
junction with a weir or other device that takes account of the rate of 
flow, water registers require too much care and are too expensive for 
use in making deliveries of water to farms. The Dethridge, Grant- 
Michell, Hill, and Hanna meters described in this bulletin are all of 
the type that register the total flow rather than measure the rate of 
flow, and to the extent that they can be made to meet the conditions 
already named, are preferable to the more simple weir or orifice taken 
singly. 

In planning and carrying out the installation at Davis three main 
purposes have been held in view : To assemble in one accessible place, 
and largely for demonstration uses, examples of the principal irriga- 
tion measuring devices so far developed; to make such tests of these 
devices as would demonstrate their accuracy under ordinary field 
conditions when compared to a standard weir and to each other ; and 
incidentally to furnish an opportunity to students at the University 
Farm to make practical working tests in agricultural hydraulics. In 
installing the various devices the effort has been made to follow prac- 
tical field rather than ideal laboratory conditions; also, in describing 
the devices and the tests made of them, technical language has been 
wholly eliminated. For the benefit of engineers, however, the full data 
of the various tests made are grouped together in the appendix. 

There have been numerous bulletins dealing with different phases 
of the measurement of irrigation water issued by the Agricultural 
Experiment Stations of some of the western states. This bulletin is 
not designed to restate what these Stations have already stated, nor 
to deal with matters of water measurement that are of chief interest 
to hydraulic engineers. The purpose is rather to describe fully, illus- 
trate by drawings and photographs, and point out the relative accuracy 
of some types of the devices that have already become standard or 
that have been in use for a sufficiently long time or on a sufficient 
scale to make them of enough public interest to warrant their installa- 
tion at the Davis field laboratory. This field laboratory offers oppor- 
tunity for the installation and testing of other irrigation measuring 
devices, and since this bulletin was prepared the designers of two 
devices have made installations there for such impartial testing as it 
is desired to subject them to. It is hoped to add to the demonstration 
from time to time, so that ultimately an example of any irrigation 
measuring device of merit may be seen installed under practical field 
conditions on the University Farm. 



116 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 



UNITS OF WATER MEASUREMENT 

The Inch. — This is a variable unit having different meanings in 
different states and even in different sections of the same state. The 
old miner's inch of California was the quantity of water flowing 
freely through an opening 1 inch square, the center of which was 4 
inches below the surface of the water standing above the opening, and 
which is equivalent to a flow of 9 gallons per minute or % cubic 
foot per second. The present statute inch of California is defined as a 
flow of one and one-half cubic feet per minute. It is measured under a 
6-inch pressure and is equivalent to a flow of H14 gallons per minute 
or % cubic foot per second. While the meaning of the inch varies 
with local practise, it is not a stream of water 1 inch deep and 1 inch 
wide, regardless of pressure. Where its meaning is clear the inch is 
a convenient unit for measuring small streams up to, say, 50 to 100 
inches, and is quite commonly used for such streams, particularly on 
many of the southern California systems. For larger streams its use 
is generally discarded in favor of the more definite cubic foot per 
second. 

The 24-Hour Inch. — This is a very common unit, especially in 
southern California, and is, as its name implies, 1 inch (the exact 
amount of which varies with locality and local custom) running for 
24 hours. Variations of this unit found on some California irrigation 
systems are the 1-hour inch and the 12-hour inch. 

The Cubic Foot per Second. — This unit represents an exact and 
definite quantity of water, viz : the equivalent of a stream 1 foot wide 
and 1 foot deep flowing at the rate of 1 foot per second. It is there- 
fore the most satisfactory unit for streams of one or more cubic feet 
per second. 

The 24-Hour Second Foot. — This is one cubic foot per second, run- 
ning continuously throughout a 24-hour period. It is equivalent to 
approximately 2 (exactly 1.9834) acre-feet. 

The Acre-Foot. — This is the equivalent of a body of water 1 acre in 
area and 1 foot deep, or 43,560 cubic feet. As already stated, one 
cubic foot per second, or 50 southern California inches, or 40 Cali- 
fornia statute inches, running continuously for 24 hours will supply 
approximately 2 (exactly 1.9834) acre-feet. 

The Acre-Inch. — This is one-twelfth of 1 acre-foot, or the equivalent 
of a sheet of water 1 acre in area and 1 inch deep. It is the unit 
sometimes used instead of the acre-foot, especially in expressing 
quantities of less than 1 acre-foot. 



Bulletin 247 



IRRIGATION MEASURING DEVICES 



117 



The Gallon. — As many irrigators receive their water supply from 
pumps and as pump manufacturers usually estimate discharges in 
gallons per minute or gallons per second, this is sometimes a convenient 
unit to use. One cubic foot is approximately equal to iy 2 gallons 
(exactly 7.4805) and 1 cubic foot per second is approximately equiva- 
lent to 450 gallons per minute or iy 2 gallons per second. 

One Thousand Gallons. — This unit is quite common in irrigation 
practise in San Diego County, Calif,, where the cost of irrigation water 
is perhaps higher than anj^where else in the United States. 

THE DAVIS FIELD LABORATORY 

In addition to the various measuring devices subsequently de- 
scribed, the Davis laboratory consists of the following elements : 

(1) Reinforced concrete lined reservoir (Pig. 1) 96 feet long, 16.5 
feet wide, and 5.5 feet deep, with side-slopes of 1 to 1, and with eleva- 
tion of 94.8 feet above datum. This reservoir has a capacity of 11,910 
cubic feet and it has been carefully calibrated. Outlet from this 
reservoir into the standardizing box and through it to the measuring 
devices is through a 15-inch vitrified clay pipe and is controlled by 
means of a 15-inch Western steel headgate. The reservoir is filled 
from a near-by well by means of a 4-inch centrifugal pump. 




Fig. 1. — Beinforced concrete reservoir, Davis Field Laboratory 



118 



UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 



(2) Concrete standardizing box (Fig. 2), 30 feet long, 9 feet wide, 
and 6 feet deep (all inside measurements) with partition 12.75 feet 
from the upper end containing an opening 5 feet wide, 1 foot above 
the bottom of the box, a similar opening 5 feet wide having been left 
in the lower end of the box. These openings are so equipped that weirs 
or orifices of desired sizes can be set in them, making it possible to 
use either a standard weir or a standard orifice in testing the various 




Fig. 2. — Concrete standardizing box, Davis Field Laboratory 



devices. Water from the reservoir is brought into the box with a 
downward flow into a slightly suppressed pool and must pass from 
the pool over a bulkhead 12 inches high and through a baffle before 
reaching the weir or orifice set in the opening in the partition already 
referred to. Four pieces of 4-inch channel iron 9 feet long are set 
directly below the baffle board and when desired furnish a spill with 
an aggregate length of 72 feet for aiding in keeping a constant head 
over the standard weir or orifice. When planning the installation 
this was considered a necessary part of the control on account of the 
water supply from the reservoir being fed to the standardizing box 



Bulletin 247 IRRIGATION MEASURING DEVICES 119 

under a diminishing head. The channel-iron spills all discharge 
through a 6-inch iron pipe into a well on the side of the main box out 
of which water spilled can be measured through a circular orifice of 
any necessary size. In the tests thus far made this spilling device has 
not been used because it has not been found necessary to maintain an 
exactly constant flow during the tests. The elevation of the bottom 
of this box is 90.6 feet above datum. 

(3) Concrete main ditch 3 feet wide, 2 feet deep, and 80 feet long, 
with vertical sides, leading from the lower end of the standardizing 
box. All devices other than the Azusa, Gage, and Riverside hydrants 
lead from this main ditch. The elevation of the ditch is 90.6 feet 
above datum and it has a slope of 0.10 foot in 100 feet. 

(4) Twelve-inch concrete pipe leading from the bottom of the 
standardizing box to the Azusa, Gage, and Riverside hydrants, the 
flow into this pipe being controlled by a 12-inch K-T valve set flush 
with the bottom of the standardizing box. 



MEASURING DEVICES FOR UNDERGROUND DISTRIBUTION 

SYSTEMS 

When irrigation water is distributed in underground pipes 
measurement is usually accomplished at the hydrant through which 
the water is brought to the surface. Three of the measuring hydrants 
used in southern California have been installed at the field laboratory. 

AZUSA HYDRANT 

This hydrant (Pigs. 3 and 4) is chiefly used in the vicinity of 
Azusa. Calif., and provides for measurement through one or more 
orifices on the center of which a pressure head of 4 inches is main- 
tained by means of a sheet-iron spill crest set at right angles to the 
orifice plate. The hydrant is in the form of a concrete box placed 
over the supply pipe line. The openings in the orifice plate are 4 
inches high and 2%, 3%, 614, and 12y 2 inches wide, giving areas of 
10, 15, 25, and 50 square inches, respectively. "When the water sur- 
face on the upper side of these openings is held 4 inches above their 
centers they will discharge respectively, 10, 15, 25, and 50 inches. By 
using different combinations of these openings several different 
amounts up to 100 inches can be measured. The water enters through 
the pipe shown in the drawing (Fig. 4). The orifices for the desired 
amounts to be turned out are opened and the others closed with slides. 



120 



UNIVERSITY OF CALIFORNIA — EXPERIMENT STATION 



By adjusting the gate below the spillway the water can be brought to 
the crest of the spillway, the area of the orifices in square inches being 
then equal to the number of inches turned out. If the water rises 
above the openings a large part of the increase will be carried back 
to the supply line over the spillway, but any increase in depth on the 
openings will also increase the amount turned out. 




Fig. 3. — Drawing of Azusa hydrant 



The Azusa box as shown has walls 6 inches thick, all sides being 
vertical and flat. The forms required in making are therefore simple. 
The box contains 78.3 cubic feet of concrete. This can be made of 
1 part cement to 4 parts coarse sand. As the walls are 6 inches thick 
it is better to use some gravel when it can be obtained. A good mix- 
ture when using gravel is 1 part cement, 3 parts sand, and 4 parts 



Bulletin 247 



IRRIGATION MEASURING DEVICES 



121 



gravel. The gravel should not be larger than iy 2 inches. The con- 
crete for this box including forms will cost from $18 to $20 under a 
large contract and about 
$30 if made singly. The 
plate with the openings 
and slides can be bought 
already made for $12 from 
foundries in the vicinity of 
the places the hydrant is 
used. The gate can be any 
of the usual types of slide 
gate. 

The average of all tests 
made of this hydrant show- 
ed the amounts in inches 
being carried through the 




Fi< 



4. — Photograph of Azusa hydrant 
from above 



openings to be 1 per cent more than their area in square inches. This 
difference includes all errors in the measurements so that these open- 
ings are seen to be very accurate. The tests showed all openings or 
combinations of openings to be equally accurate. The box will there- 
fore measure as accurately as is required. The openings are not as 
closely adjustable to the amounts turned out, however, as they are in 
the case of the box of the Riverside Water Co. 



GAGE HYDRANT 

This hydrant (Figs. 5 and 6) has been developed, and, so far as 
is known, is only used by the Gage Canal Company, of Riverside, 
Calif. The main box is of mortar 2 inches thick and is made in the 
material yard and seasoned before setting. The concrete is made of 
1 part cement and 3 parts coarse sand, mixed quite dry and thor- 
oughly tamped. The bottom is cast separately and the top cemented 
to it in the field. The dimensions of the box are shown in the drawing. 
The weir crest consists of %-inch by li/o-inch iron cemented to the 
sides, giving a final opening of 10 inches wide and 10y 2 inches high. 
One man makes 2 boxes in a day. In making one box 2% sacks of 
cement are used. The company charges $10 per box, with weir, not 
installed. The outlet chamber into which the water goes after passing 
over the weir is omitted from the drawing. In the hydrant installed 
at Davis a half section of 18-inch pipe is used for this purpose, as 
shown in the photograph. When the hydrant is not in use the valve 



122 



UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 



shown in the drawing at the end of the pipe is kept closed. When 
in use the valve -is opened to the desired extent and the water rises 
from the valve and flows over the weir. The amount flowing is de- 
termined by measuring the depth of the water in the box above the 
crest of the weir and either figuring the discharge or taking it from 
a table. The depth of water on the crest is usually obtained by meas- 
urement from a bracket set level with the crest at the back side of the 
box. After the water passes the weir it can be caught in various ways 
and carried to its point of use. Generally this is done by letting it 




Fig. 5. — Drawing of Gage hydrant 



Fig. 6. — Photograph of Gage hydrant 



fall to a pipe below and carrying it through pipe distributing systems 
or directly into a distributing flume. 

In the tests with this hydrant it was found that the amount of 
water discharged for any given depth was greater with this box than 
it would be with a standard 10-inch weir. This is due to the nearness 
of the sides of the box to the sides of the weir and to the velocity con- 
ditions in the box. The amount of this difference increases as the 
head increases, being as much as 35 per cent at the higher heads. In 
practice the principal source of error in using this box will be the 
difficulty in measuring the depth over the weir closely. In the tests 
this was done with special gages enclosed in stilling cans, but even 
then it was difficult to get the depths correctly. Measurements in 
open water with a rule would vary much more. 



Bulletin 241 



IRRIGATION MEASURING DEVICES 



123 



RIVERSIDE BOX 

This is shown in figures 7 and 8. It consists of a shallow box set 
over the end of the delivery pipe line. The water enters through the 
bottom of the box and is measured out through an adjustable cast- 




'. — Drawing of Riverside measuring box 

iron measuring plate in the end. The opening in this plate is 5 inches 
high and by moving the iron slide gates it can be varied in width up 
to 14 inches. With this gate, however, there is no provision for hold- 
ing a constant head or 
pressure above the opening. 
The top of the plate is 4 
inches above the center of 
the opening. Thus if the 
slides are set so as to hold 
the water surface at the 
top of this plate the dis- 
charge in inches will equal 
the area of the opening in 
square inches. The area 
of Ihe opening is the width 
in inches multiplied by 5. 
Marks one inch apart are 




Fig. 8. — Photograph of Riverside measuring box 



124 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 

made on the plate to assist in measuring the width. The method of 
carrying the measured water away is not shown on the drawing but 
is shown in the photograph. The water is usually dropped into another 
pipe system to be distributed for use. Care should be taken so to place 
the outlet chamber that water passing through the gate will always 
have a free fall. 

The Riverside box is made of concrete 4 inches thick and contains 
18.4 cubic feet of concrete. The concrete can be made of 1 part 
cement, 3 parts sand, and 4 parts of gravel not larger than 1V 2 
inches in diameter. This will require 3 sacks of cement for the box. 
The box can be made with a cover as shown in the drawing. The plates 
containing the orifice can be purchased already made. The forms for 
making the concrete walls are simple as there are no curves and all 
sides are vertical. The cost of the plate is $2.25, the concrete will cost 
from $3.50 to $5.00 for material, forms, and labor, and the cover will 
cost about $1.50 more. These boxes are made and installed by the 
company for $10.00. 

In the tests of this device the average difference between the num- 
ber of inches actually received and the area in square inches of the 
opening was about 2 per cent. Some of these tests gave more and 
some less than the measured amounts. For all tests the area in square 
inches of the opening averaged 1 per cent greater than the inches 
actually received. The tests show that where care is used to adjust the 
width of the opening to the amount running this box will measure 
water very closely. 

While the Riverside box is of the type used on underground pipe 
systems, the measuring plate used in it can be set in open ditches if 
desired. The box is sufficiently large so that the water passes through 
it without much agitation and can be brought to the top of the opening 
plate quite closely. There will generally be some leakage around the 
slides but these can be wedged tight if necessary. The box shown 
will measure amounts up to 75 inches. 



FOOTE INCH BOX 

This structure is shown in figures 9 and 10. It consists of a box 
having two principal parts, the larger part being merely a section of 
flume set in the main channel of the supply lateral and the smaller a 
spill and measuring chamber. On one side of this smaller portion there 
is a discharge opening in which a slide moves horizontally. The other 
side of this side box or flume is a spillway. Gates are arranged as 



Bulletin 247 



IRRIGATION MEASURING DEVICES 



125 



shown at the upper end. so that water can be turned into this side box 
as desired. This is done by putting in as many flash boards across 
the supply lateral as are needed to crowd the water into the side box. 
The slide on the miner 's inch opening is then set so that the water in 
this side box stands level with the crest of the spillway. The crest 
of this spillway is placed 4 inches above the center of the opening. 
The opening is 4 inches high. Thus when the water stands level with 
the spillway the width of the opening of the slide multiplied by four 
gives the number of inches flowing. 




Fig. 9. — Drawing of Foote inch box 



This box does not require much fall in the supply lateral. The 
crest of the spillway should be set so that the water in the main chan- 
nel will be at least 3 to 4 inches below it. The water in the ditch above 
can then be checked up with the flashboards until the water in the side 
box comes level with its crest. The ditch into which the measured 
water is turned must be lower than the main channel by over one foot. 
The water in the outlet flume should not rise within about 3 inches of 
the bottom of the slide opening. If the water in the outlet flume does 
rise above the bottom of the slide opening, the conditions for measure- 
ment are changed and the discharge is smaller than with free fall. 



126 



UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 



In the tests of this device the amount of water supposed to have 
been passed, as measured by taking the area of the slide openings, 

averaged 4 per cent greater 
than was actually run. The 
error did not vary with the 
amount of the discharge. 
From these tests it appears 
that the slide can be set 
within an average 4 per cent 
of correct if care is used. 
This box will measure 
water up to 150 inches sat- 
isfactorily under conditions 
to which it is adapted, al- 
though it is not in general 
an economical box to use. 
It requires as much fall from the supply lateral as a weir, besides 
some fall in the lateral itself. It also takes as much lumber as is 
required for a check and turnout in the supply later and a weir 
below. The weir will give more satisfactory measurements and has 
no slides to leak if too loose or to stick if too tight. The inch box 
was used a good deal in the earlier days when water was measured 
mainly for mining but is built but little now for irrigation use. It 
has one advantage over a weir in that the amount being measured 
can be determined directly from the area of the slide opening, no 
tables or figuring being needed. With a weir, tables must be used 
giving the discharge for weirs of different lengths at different depths. 




Fig. 10. — Photograph of Foote inch box 



WEIRS* 

In sections where the irrigated lands have a considerable slope, so 
that water can very easily be led from the supply ditches or laterals 



* No attempt is made in this bulletin to present a broad and full discussion 
of weirs, only enough being given to enable the farmer who is unfamiliar with 
water measurement to understand their use in irrigation. The weir tables that 
are given are those that are generally used in irrigation practise and are there- 
fore based on the well-known formulas. Engineers have recognized that these 
formulas do not apply throughout the wide range of conditions met in the field 
and for that reason numerous engineers have made experiments designed to 
correct the formulas for the conditions to which the Francis and other formulas 
do not properly apply. The Office of Experiment Stations, in co-operation with 
the Colorado Agricultural Experiment Station, has installed and fully equipped 
at Fort Collins, Colo., an hydraulic laboratory in which a large number of such 
experiments with weirs have recently been made by V. M. Cone, irrigation 
engineer, and assistants. 



Bulletin 247 



IRRIGATION MEASURING DEVICES 



127 



to the land without having to check the water nearly as high as the 
ditch banks, some form of weir is the most common type of measuring 
device. Taken singly, however, a weir, like other non-mechanical meters, 
measures the rate of flow and does not indicate the total quantity 
delivered. In conjunction with a water register (Fig. 26), which 
graphically records the depth of water passing over the weir, or in 
conjunction with such a device as the Hanna meter (Fig. 25), which 
may be arranged to read directly in acre-feet, measurement by means 
of a weir gives entirely satisfactory results. Where conditions permit 
its use the weir is thus far the generally accepted device for measuring 




Fig. 11. — Measuring water with a small wooden Cipolletti weir 



lateral diversions from main canals. It is also an accepted standard 
device for testing the rate of flow from pumping plants, just as it has 
been the standard device in the tests that have been made of the various 
devices installed at Davis. Small movable weirs (Fig. 11) are con- 
venient for use by farmers for measuring the water carried in their 
individual ditches or discharged by pumping plants. 

Three types of weirs are chiefly in use in irrigation practise ; viz : 
the Cipolletti weir, the weir extending the entire distance across the 
ditch or flume carrying the water measured, known as the weir without 
end contractions, and the rectangular weir that does not extend en- 
tirely across the ditch or flume, known as the rectangular weir with 
end contractions. The first two only of these are installed at Davis 
and described in this bulletin. 

Briefly, a weir is merely a board or other crest set across a stream 
or other water channel and over which the water carried is made to 
flow. If the velocity of the water directly above the weir, known as 



128 



UNIVERSITY OF CALIFORNIA — EXPERIMENT STATION 



the velocity of approach, is very small and due only to the falling of 
the water over the weir crest, the quantity of water passing depends 
entirely on the depth of the water over the crest and the length of 
the crest. In the case of the rectangular weir with end contractions 
the discharge is not proportional to the length of the weir crest. Such 
a weir is not, however, described in this bulletin. In fact, the discharge 
is not precisely proportional to the length in the case of the weir 
without end contractions, but is so nearly so as to involve no error 
of consequenoe by assuming it to be. As tables have been prepared 
that show the quantity passing over both a Cipolletti weir and a weir 
without end contractions (as well as other types of weirs), measure- 
ment with a weir only involves measuring the depth of water over the 
weir crest and reference to the appropriate table to determine the 
quantity passing for the given depth and crest length. 



OIPOLLETTI WEIR 

This weir, as installed at Davis, is shown in figures 12 and 13. The 
length of weir and size of box to make are of course dependent on the 
quantity of water to be measured. In general, it may be said that a 
Cipolletti weir should be small enough so that the amount of water to 




Fig. 12. — Drawing of Cipolletti weir and weir box 



Bulletin 24' 



IRRIGATION MEASURING DEVICES 



129 



f ***** 




-'-<''• mm 


^ - =r 

r t 

i ' v; 


i iVli 


■ m 


■■V T£ 


' \ V 


L 


... ,_. .' .. \ 1 



Fig. 13. — Photographs of Cipolletti weir and 
Hanna meter 



be measured will never give less than a depth of one inch over the 

weir crest, and large enough so that the depth will never need to be 

much more than one-third 

of the crest length. Care 

should also be taken to see 

that the weir crest is long 

enough so that the water 

can be measured without 

raising it higher over the 

weir crest than is permitted 

by the available fall. A 

number of other conditions 

are usually laid down as 

necessary for the weir. The 

most important of these, 

briefly paraphrased, follow : 

1. The distance from 
the crest of the weir to the 
bottom of the canal or floor 

of the weir box should be at least three times the depth of water on 
the weir. That is, with an 18-inch weir intended to measure up to 
2 cubic feet per second, which requires a depth on the weir of about 
6 inches, the crest of the weir should be about 18 inches above the floor. 

2. The distance from the ends of the weir crest to the sides of the 
weir box should be about twice the depth of the Avater on the weir, 
or, say, from 10 to 12 inches in the case of an 18-inch weir measuring 
about 2 cubic feet per second. 

3. The bottom and sides of the weir notch should be bevelled on 
the down-stream side to give a narrow edge. The use of a galvanized 
iron crest is quite common and very satisfactory, but not necessary. 
Sometimes thin pieces of strap iron are fastened on the up-stream side 
of the weir notch. In other cases the board in which the weir notch 
is cut is merely bevelled down to a crest thickness of one-eighth or 
one-quarter of an inch. 

4. Water should not be allowed to approach the weir with a velocity 
exceeding 6 inches per second. Also, it should flow to the weir in a 
smooth stream free from eddies or swirls. Both of these conditions 
are most easily met by placing the weir in a straight section of the 
ditch. 

5. The water passing over the weir should, if possible, have a free 
over-fall. Where necessary, however, it may rise to the level of the 
weir crest without appreciable error in the measurement. 



130 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 

6. The depth of water on the weir crest must be measured suffi- 
ciently above the weir to be free from the downward curve of the 
water as it passes over the weir. For convenience in making this 
measurement of depth a stake with its top level with the crest of the 
weir is usually set at one side of the ditch 2 or 3 feet above the weir, 
the measurements of depth then being made from the top of this stake 
to the top of the water. 



Cipolletti Weir Tables 

The tables below give the discharge over Cipolletti weirs from 1 to 
5 feet long. For lengths of from 1 to 2 feet the length of weir crest is 
given in inches and the depths in inches and feet (Table 1). For weirs 
with crest lengths of 3, 4, and 5 feet the lengths and depths are given 
in feet only (Table 2). If it is desired to measure the discharge in 
inches instead of cubic feet per second, multiply the cubic feet per 
second given in the table by 50, if the old customary California miner's 
inch is desired, or by 40, if it is desired to use the statute miner's inch 
of California. 



Bulletin 247 IRRIGATION MEASURING DEVICES 131 



^ © OO O 05 © Ol CO (O O M OO N © O 1Q a ^ oi ■* a •* a 
<M O O i— I r-l i-H rl <M N M CO CO ■* "HH IO IO IO CO (O l> l> 00 M 



CO 

CO 

• „ © CO O CO IO O r- I lO Ol CO © O HH 00 CM t^ rH CO rH CD O tO 

6,3 ^ O O i-l iH iH iH CM N (M CO CO ^ -* -^ lO lO © © t> O CO GO 

II 

<J N CO t* Ci CO IO 00 O *<HH 00 rH IO OO CM CO O IO OS CO CO CO N (M 
J eqOO O rH i— I i— I CM CO N CO CO CO -<HH ->HH IO IO IO © © t> N CO 
P ' * 

" _i IO *>■ OJ (M •* CO ffi CO CO O CO t- O i* S N (O rH IO O rfl CI 

M (M O © O rH rH rH rH. CM <M CO CO CO H^ "* H} IO lO «3 (O l> S t~ # 

O 

as 

Q 

&q _ <HH t- CO O] CO N CO N IO CO M IO 00 <M IO O CO OO M N O IO 
En m OO O rH rH rH rH <M CM CM CO CO CO -* ■* IO IO W (D © l> S 
P * " 

Oh 

o 

ffl ^ ® 00 H CO (D t> rH HH S O CO CO O CO 00 rH IO a CO tO H 
q" h O O OrHrHrHrH N (N N CO CO CO •* ■* Tt< IO IO IO (D © N 
£ 

o 
o 

H 

CO «H CO 00 © CM IO I— © CM IO 00 rH rj( CO h IO CO iM IO O) M t- 

03 j£ rH O O OrHrHrHrH CMCMCMCMcO CO CO HH "tf tH O W W © (O 

W js • • 

EH .s 
w 

w 



Bj t-3 |> H/i CD t> O H ■* tO CO H tH S O CO IO CO (M IO CO (M tD O -* 

H m ,, rH © © OrHrHrHrH H <M (M (M CO CO CO CO "HH HH tj* IO IO (D (O 

M i- 1 « 



p 



►, H (O TH IO N Oi H CO IO S C CO IO OO rH CO CD © CO IO OS CO CD © 



OO OOrHr-lrH rH CM CM CM CM CO CO CO -* -* Tj( ^ W IO <D 

So * 

O PI 

O ^ 

to -H IO (O O) O CO <# CO Ci rH HH CO CJ rH HH 00 © CM CO © CM CD 

CO rHOO OOrHrHrH rHrHCMCMCM (M CO CO CO ^ ■* ^ IO W W 

w • • 

K 
o 

i— i 

.. rt< H< IO CD 00 C5 CM CO IO O0 O OJ t)( N OS IM IO l> OCOt^OiCM 
l£ rHOO OOOrHrH rHrHCMCMCM CMCMCOCOCO tJHt^^^IO 
CM • 

O 

EH 

<M 

1-1 coCOHH IO 00 C5 rH CM HH CD 00 rH CO W l> Oi (M IO N O CO (D a 

M rHOO OOOrHrH rH rH rH CM CM CM CM CM CO CO CO H^ HH tjH H< 



h-i „ CO HH lOt^OOOrH CO IO l> Oi H COIOt-OCM ^ t> O (M IO 
Eh ^OO OOOrHrH rHrHrHrHCM CMCMCMCOCO CO CO HH HH HH 
Eh rH . . 

w 
p 
p 

§ 

5 



CM CM CM CO CO HH HH IO IO IO © «0 N N CO CO CO Ci Ci © © © 

13 



-^ HH O © l> O0 Q O rH CO CO HH IO COt-OOOiO H (M ■* IO <C 

feOO OOOOrH rHrHrHrHrH rHrHrHrHCM CMCMCMCMCM 



K W « r£ ^ ^!^ # ^ ^^^C^^ r^r^C^r^ ^ ^ ^ r£ 

O >-H rHrHi-H rHrHrHrHrH CMCMCMCMCM CM <M CM CO CO 

go 



132 



UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 



w 

h-H 




LO 

OS 


o 

c 


co 
— 


-] 


L~ 






>H 


•H 


'- 1 


^ 


b- 

CO 














CO 


CO 


o 

OS 


CO 

OS 


CM 


o 


CO 

— 



< 
p 

o 
o 

Q 
Eh 

Pm 

o 

O 

Q 

O 

o 

w 

CO 

cd 

Oh 

H 

w 



(M 00 CO 00 CO 
00 QO OS OS O 



00 CO QO CO 00 

£j t- oq oq os os 



a "* Os ^tf Os co 
^ s t- x oo a 



^ a «D N M LO r-i GO ^ rH CO LO oi a © 

N N CO "* "* LO CO CO l>- 00 QO OS O O rH 

r-i rH r-" r-i r-i rH rH r-i r-i i-H r-i r-i N CXI* oi 



T. ^ O © (M 00 tH r- i t- T*< O OO CO O t- 

rH OQ CO CO tjh -^ Ifl (O !D N QO 00 OS © © 

r- 1 rH r- 1 j— | rH H rH r-> r- 1 i— i r- 1 r-i r-i CM* OJ 



1< O) lO O (O H t> 11 O t> CXI O LO rH GO 

rH rH CM CO CO H^ HH lO © O t> O0 OO OS O) 



CO00COQ0CO CO CO O IO (M L— CO GO CO © 

O O rH r-1 <M OCICO^TtHlO O O © N M 



w 


z 


r-J 




PQ 


o 


<j 


z 


H 


*2 




"-~ 




-r. 




M 




w 




O 




Z 



CO t— rH lo OS W N N © H i rj o LO OS "* 

GO 00 OS OS OS © O rH rH CM W M M M ^ 



00 rH LO OS C\l © O IO a <* » M © O LO 

b- CO GO 00 Oi OS © © © rH H CXI Ol M « 



CI CO OS CO CO © CO 00 rH CO O ■* 00 H 50 

I- I- N 00 Q0 OS OS OS © © rH rH rH CM <M 



c 
















H 
















Ol 
















C" 1 






rH 


rH 


b- 


r- 1 


-r 


CO 






IO 


»o 


»- 


CO 


co 


« 
































W 
















£ 
















M 






b- 


o 


CO 


CO 


OS 


r< 




- 1 


TtH 


1 ~ 


1- 


»o 


kO 


















W 
















J 
















Hi 

































Cm 






















































rH 


r-{ 


Cl 


CM 


CI 


fo 






b- 


CO 


OS 


o 




c 


w 


N 


CM 


CM 


CM 


CO 


CO 


W 














rt 


T3 














a! 
















< 


s 


c 


r^ 


^ 


^ 


# 




o 




»— 


CO 


CO 


CO 


co 


CO 


QQ 

















b- © Tfri L- © THt^rH^OS IM © Ci M '- 

!D I- N l-» O0 00 00 OS OS OS © © © rH <"-i 



CM LO CO rH ^ t- O ^ b- rH T^ CO H TJ< « 

© © © t>. b b- 00 OO 00 OS OS OS o o o 



CO CO -HH -HH 'O 

ca co thh lo co 
co co co co co 



CO — H "HH Ttt Tfi 



CO LO CO CO b- 
t^ GO OS © rH 

co co co ^ th 



Tf* "^ T^ "HH UO 



b~ CO 00 00 OS 
CM CO r* LO CO 



vOO v-j* x50 ^1 v^O 
lH^ r>- ©^ ri^ 10^ 

IO IO O IO w 



Bulletin 24< 



IRRIGATION MEASURING DEVICES 



133 



K H OO lO M 
CI CO CO t)h io 

ci" cq" cq" cq' ci 



rH CI !D rf CI 
CO q b- CO OS 
CI <?"]' Oq' CM* Cq' 



CO CO CO CO CO 



CO CO CO CO 



t)H i— 1 00 io CO 

i-j cxi cq co •<# 

CM* CXI* <m" cq' cq' 



05 <» ^ N O 
TjH "O CO L- 00 
Cvi CQ CM* CQ CM 



cm cq co co co 



h io co h a 
ci co th io io 
co' co' co co co" 



IO rH GO IO Cvi 

© r-1 t-n cq CO 
cxi ci cq" oq" cq' 



CO r- 1 ao IO <M 
OS © © rH CXI 

T-" cxi cm" cq" cq* 



CO t- CO © 00 
M Tj| IO to CD 
CXI OT CM* OQ <M* 



GO CD CM 00 CD 
CM CO TJH "rtf IO 

cxi cxi cxi cxi cxi 



»o on o co co 
b. oq cs as © 
cxi cxi cxi cxi co* 



oq a vO io cxi 

CO !D l> OO C5 

cxi cxi cxi cxi cxi 



CO O CO CO CO 
i-H CXI CXJ CO TlH 

co' co co co co* 



CM CO CO CO CO 



T— I !— I CXI <M 



b- tH O L- CO 

r-i cxi co co ^ 
cxi ci cxi cxi cxi 



O CO CO rH CO 
IO IO CO t- b- 
cm' cq cxi cxi cxi 



TtH rH CO CO Cvi 
CO OS OS © rH 

cq* cxi cq' co' co* 





o 


















w 






















(Tv 


b- 


71 


00 


th 


j— | 




Q 




^H 


b- 


00 


GO 


OS 


q 




o 

c 






m' 


r-i 


rH* 


r-i 


ci 




















H 


















GC 
















' — s 


02 

W 
P4 




00 


b- 


n 


GO 


TtH 


o 


CO 

3 


03 


H 


CD 


i- 


1 - 


CO 

rH 


OS 


.e 


Fh 


C 














^ 


H 


"- 














Eg 


W 


- 














o 


ft 


r-i 


t- 


GO 


CO 


CO 


~r 


OS 


o 


O 


H 


i— 


IO 


CO 


CO 


i- 


1 - 


*»— ' 


*S 




rH 


T— f 


,_' 


i— i 


1 — 1 




m 


£ 














1 

i— 1 


P 


c 














E 


fc 




cc 


OS 


co 


OS 


xH 


cs 


A 


5 


iH 


Th 


iq 


iq 


CO 


cc 


PQ 


a 


w> 




r-* 


rH 


r-i 


i— i 


r-i 


< 


c 


3 




















IO 


c 


TJH 


OS 


CO 


oo 




H 

o 






rtj 


TjH 


-r 


iq 


kO 








r-' 


l-i 


r-i 


r-i 


i—" 




















£ 

















ci cq ci oi cq 



ci cq cq cq 



^ H 'O rt l> 
GO OS OS o o 

i— " r-i r-i cq* cq' 



r 

CO 




IO 


00 


CO 


cq 


CI 


CI 


CI 


CI 


IO 

ci 


CC 


b- 

CO 




o 


CI 


CI 


cq 


CI 


CI 



cq oo t* o co 
rH i-i cq co oo 
ci cq' cq' cq cq' 



O IO rH t— CI 

q q ^ r-i cxj 
cq' cq' cq* cq" cq' 



oo cq CO CO CO 
oo as cs q o 

i-H* r-i rH* CXI* CX]* 



O b- CO O CO 
t- b- GO OS OS 

cq* cq' cq' cq' cq* 



CO Cq GO IO rH 

iq © co i> oq 
ci* ci cq* cq* cq* 



cq oo co o »o 
^ HH iq co co 

cq' ci" cq' cq" cq* 



00 CO O0 rf 

CM M CO ^ 

cq' cq* cq' cq* 



rH IO OS OO t- 



Ul 


rH 


. 


CI 


C 1 


CQ CQ 


<& 




r— : 


I— 


rH 


r-i r-i 


























>■-* 




cq 


IO 


■CS 




c^ 


Ol 


rH 


r^ 


rH 








r-i 


n 


rA 




r3 












J 












o 












PL, 












—1 












Q 




OS 


o 


o 


O rH 


fe 


+j 


b- 


cs 


c 


rH Cq 


o 


w fe 


^ 


-* 


iq 


iq iq 


a 












a 


Tj 










03 












< 




^ 






r^r^ 


u 




»o 


IO 


CO 


CO CO 



rH cq cq cq co 

CO 'HH IO CO b- 

io io io io io 



co co co co co 



CO rJH -Hrl IO >0 
OO OS O rH cq 
LO IO CO CD CO 



r^ ^ S£ ^ 

b- L- b- b- 



lO CO CO t^ b- 
CO ■* IO CD l> 
CD CD CD CD CO 



^ ^ ^5 35 

b- b- t- OO O0 



134 



UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 



< 
P 

o 

Eh 

O 
ft 

o 
w 

Eh 
P 

Cm 
§ 

O 

O 

O 

o 

w 

03 
Ph 

Eh 
W 
W 

O 



H- 


eo 
OS 


© 


^ 


OS 


CO 


CO 


Tt* 


-*-' 


rh 


X 

CO 


b- 

b- 




OS 


ci 


CO 


CO 


CO 


CO 


TjH 


Cl 


CO 


cc 


CO 


GO 


CO 


eo 


CO 


CO 


CO 


CC 

CO 




iH 


OS 

in 


CO 
CO 


CO 


CO 


CO 


CO 


CO 



OS 

CI 


b- 


CO 

-r 


cc 
l.c 


-1- 
cc 


-f' 


rH 


Tji* 


Tf 


tH 


C) 


cr. 


00 

CI 


1- 

CO 





OS 


o 


OS 

© 


X 

1— 


CI 


CO 


~t' 


-f-' 


~f 


■* 


CO 


00 


c 
cr. 


OS 
OS 


CO 

c 



co co co co Th 



c 

CI 


X 

C| 


eo 


Cl 


OS 


X 


CO 


Cl 


o 

X 


b- 

X 


eo 


CO 


eo* 


CO 


co' 


CO* 


CO 


CO* 


CO 


eo" 





OJ 


© 


Cl 


X 
rH 


to 

Cl 


i—i 
eo 






CO 


eo* 


CO 


DO 


ed 


a' 1 


CO 


X 
X 


0s 


© 


X 

© 


-*■ 


si 
o 




<N* 


CM* 


eo 


eo 


eo" 


4 


b- 


b- 


OS 


oq 






"53 




c<i 


ci 


<M* 







O O M H N 

rt< Tin io cq co 
eo' eo eo eo" co* 



<M X 
CNI <M_ 

co' co" 





X X X OS OS 


+J 


X OS O rH <M 


fc 


CO CO b- b- b- 



W c " ^ *# ^ ^ ^ 

H QO X X X X 



O O O iH 
thh io CO b- 
b- b- b- b- 



x os os os cr. 



Bulletin 247 



IRRIGATION MEASURING DEVICES 



135 



< 

& 

% 

c 

HH 

o 



1 o 
•J in 






i — I -i — I t — I i — I Gvl 



oo cs os os os 



o 

00 


CI 

rH 


-* 

-* 


lit 


o 


CI 

CO 


DO 

CO 


CO 
CO 


00 

CO 


HH 

CO 


Cl 


(35 


io 


o 
o 


IO 

Cl 


co 

CI 


CD 
CI 


C] 


Cl 


I- 



05 H ^ «D CO 

eo t> q m «o 

HH tj" io io* io 

co co co co co 



N O M ffl Ol 
C\l IO t- OS rH 

<m* oi cd <m" co' 



(M O CO N O 
OO O r-i CO iq 

os o o o" o" 



rH CO CO OS Cl 

O CO CO OS CO 

CO CO CD CO l>" 

CO CO CO CO CO 



O N M Ci IO 

oo # © co iO oq 

00 OS OS OS OS 

(M Ol (M (M CM 



<M CO O CO t^ 
"tf CO OS rH CO 


rH IO © HH OS 
CO 00 rH CO IO 


CO CO CO HH rH 


rj< •* IO W IO 



H^ CO <M i— I O 
t- OS rH CO IO 

CD O rH r-H rA 



CO 00 CD CXI HH_ 
rH i-H CXI C\l CO 



S ^ 



CO CO CD t- t>- 



I- t- t- L^ L~- 



CO O xM OO Cl 

© cq M h to 
00* oo oo" oo" 00* 



t~ rH CO © IO 
t^ OS © CO CO 

co' oo" os* os' os' 



«M US 

4 



OS 

I— 1 


IO 
CO 


rH 
CO 


00 

CO 


CO 

<* 


00 
IO 


o 












IO 
rH 


O 
CO 


io 

Cl 


CD 

CO 


SO 

CO 


CO 


© 












rH 

rH 


IO 
rH 


OS 


CO 
Cl 


Cl 


Cl 
CO 



rH o OS oo 00 
CO t^ b- 00 OS 



CD r* CO CO © 
00 OS O rH CM 



IO rH b- H^ O 

(6 O l> CO OS 



CO t- OO OS 

o o o o 



o o o o o 



rH CJ CO H^l IO 
l — 4 i — ^ i — I i — ^ r— H 

© © © © © 



O O O O O 



136 



UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 



£ "Si 



■* OO H ■* L^ 

5D C5 M © Oi 

N N OO CO X 

CO CO CO CO CO 



00 


CO 


GO 


CM 

00 


cc 

CD 


o 

o 


00 


X 

CO 


CM 

o 


CO 

CO 


O 
b- 


LO 

- 


o 
-1- 


b* 


03 

- 


OS 

00 


OS 


OS 

00 


c 


O 


Tfl 


— 


r-i 


CI 




C\l 


00 


00 


co 


— 


IT 


7i 
b- 


CO 

OS 


CM 


CM 

IO 


o 

CO 


b- 


00 


I— 1 
CO 


Oi 
GO 


co 


^ 
^ 


C<1 


OS 
Oi 


b- 

C) 


oo 


r—i 
00 


— 
00 


00 


CM 
00 


cm 

CO 


CO 
00 


CO 

00 


00 

00 


CO 

CO 


CO 


00 


-t- 

00 


CO 


CO 






co co co oo co 
co o co io co 
io' co co" co' co 



- 

c 


re 


o co ,— 

CD CO r- 


t> 


b- 


b- b- cc 



Z 

> 


o 


b- 

co 


CC 

00 


cc 

c 


cc 

CI 


b- 


3 


CM 


71 


00 


re 


00 


STj 
















© 


o 

IO 


IO 

CO 


o 

CO 


io 

OS 


o 

T— 






OS 


Oi 


Oi 


OS 


c 



b- 

cc 


I- 
co 


co 
o 


CI 


OS 

— 


00 


00 


^ 


^ 


Ttl 



r-i CM CO ^ IO 

o o o o o 



CO CO CO OS OS 



O T-H 

b- Oi 


CM CO 

T-l CO 


i~ 


^ T^ 


IO IO 


IO 



CO b- CO 
O O O 



OS 

cc 


OS 


CI 


OS 

-T 


CD 


OS 


cr. 


c 1 


o 

CM 


CM 



>o CO 00 OS i— 
b-; OS r-J CO CD 

IO* IO* CO* CD* CO 



i— I CM CO Tfi IO 



CM r*H CD CO O 
CO b-- GO OS r-1 
rA r-* r-" t-H CM* 



b- -# r-H OS CO 
OS O t-H i—l CM 



CM CM CM CM CM 



go os o o r-i 

b- CO O r-j CM 
tH* <—' CM* CM* CM* 



- 

OS 


kO 

— 


OS 


00 


OS 


CO 


OS 

b- 




r 


co 
: i 


CI 


CO 


r: 


00 


CO 


CO 


00 


r: 


^ 


^ 


00 




kfl 
kO 


b- 

CO 


OS 

b- 


T-H 
OS 


co 
o 


CD 


GO 
CM 


— 



t-H tH tH CM CM 



CM CO CO CO CO 



00 b- b- CD CD 
i-J CM CO ^ kO 
CM* CM CM CM* CM 



t-h CM CO rti IO 
CM CM CM CM CM # 
O O* O O O 



CO b- CO OS o 
CM CM Od CM CO 

o* o* o o o 



r-l CM CO tP LO 

co co co co co 

© o* o o* o* 



BULLETIN' 247 



IRRIGATION MEASURING DEVICES 



m 



■B © 





OS 


I—, 


c. 


00 


-t" 


-h* 


id 


id 


id 


iq 


CO 

oq 


i—i 


OS 

CO 


fc- 


id 

CO 


id 

OO 


CD 

CO 


CD 

CO 


CO 

CO 



LO O CD (M 

01 LO OS Ol CO 
CD CO* CO* t>-" fr-' 

"^ "^ "^ "^ ^ 



CD rtl Ol i-l OS 

as oi lo oq © 

CD* fr-' t>" fr-" 00* 

co co eo co co 



fr- CO OS lO -— 

Oi co q © Tjj 

t-I oo" 00 oi OS 

T*H Tt* -+ -*fl ^* 



CD r _ j ,_, ,_! ,_, 



CO 
OS 


fr- 

os 


00 
OS 


OS 
OS 


O 
© 


O 


O 


CO 

© 


-t" 
© 


lO 

© 


CD 
© 


L- 

q 


CO 

o 


OS 

q 


o 


r-H 


r-H 


r-H 


rH 


0Q 


Ol" 


01* 


ol 


~\ 


Ol 


oi 


oi 


oi 


oi 


oi 



a J 



CD fr- fr- fr- fr- 



01 


CO 
lO 


Ol 

00 


"3 


"* 


• O 


• o 





CD 


CO 



N 00 OO OO OO 



Ol Ol Ol Ol Ol 



LO 00 O CO CD 

© oi to fr- os 

OS os' OS* OS* os' 



Ol Ol Ol Ol Ol 



OJ o 



rHH rfl rft -"HH LO 



t*I CO © CO CO 

io co oq os # q 
co' co' co" co' ^ 



IO 
01 


-1 


o 

CO 


fr- 


IO 

OS 


co 


CO 


lO 


X 

CO 


L^ 

oq 


IO 

q 


01 




CO 

eo 


01 

oq 


id 


id 


id 


to 


id 


co" 


CO 


CO 


cd 


CD* 


fr-' 


1-" 


I-' 


fr-" 


i- 


3 
01 


CO 


oo 


01 
CO 


CD 
fr- 


o 
os 


c 


c 
01 


CO 


OS 


CD 


o 

X 


IO 

OS 


o 


CO 

CI 



Eh 
En 


43 














W 


to 














►■"] 






IO 


to 


to 


IO 


to 


Oh 


o 
co 


co 
oi 


oi 


oq 
oi 


os 
oi 


q 

00 


















5 
















fe 
















































w 


K 














a; 


T3 


0) 


,-H 


Ol 


CO 


-H 


to 


<J 


TtH 


"*. 


-h 


-h 


-+ 


H 


CP 


«n 


©' 


d 


CD 


© 


d 


o 


HH 














a: 

















■^ T^H ^H r^H 



LO LO CD CD fr- 
i-H Ol CO_ TtH iq 

co" co" co* co* co* 



co fr- co os © 

"* ^ Tt* ■* 1C 

d © © © ©' 



co co co -t •* 



r-H Ol CO -f IO' 
IO IO IO IO LO 

d d d d d 



IO LO LO CD CD 



CO LO CD OO OS 

oi co tjh lo q 

tWH Tt< Tt^ "^ T^ 



CO fr- GO OS o 

LO LO LO LO CD 

d (6 <£ d> S 



138 



UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 





I© 


o t- 

CD OS 


TjH O l>- 

m t> q 


CO 

CO* 


u 


r-l r-H 

w w 


<m* eg co 

wow 



TfH CQ CO CO CO 

rjn CO iH W OS 

CO* CO tJH rJH rti' 

w w w w w 



r— | 

CO 


OS 

so 


CO 

c 




CO 

oo 


w 
w 


w 

w 


to 

w 


CO 
w 


co 
w 



►3 "So 

3 j 

o 

ft 



'5 o 



A 9 

CO 



H (M M ■* LO 
i— I i-i r-H l-J 1— I 
cxi CX* CO* <M* <M* 



CO O CO t- r- 1 

CO CD CO O CO 

rH i-* i-H* (M* CM* 

(M N (M (M (M 



CO <M Oq Cvl CQ 



CI CXI CvJ C\l CXI 



O O rH <M CO 

i-; q « to os 

OS* d d o" d 

ci co co co co 



w 
w 


OS 


CO 

© 


C3 W 


CO o 


WOO 
CvJ W t- 


ci 

CI 


ci 

CJ 


CO 
CJ 


CO CO 

cq eg 


CO* Tt* 
<M CXJ 


cm cq cq 



CO t- 00 OS o 

Tt^ t(H t^i ^n W 



© o 
a; . 



CO CO CO CO CO 



OS OS OS OS OS 



o o o o o 



N t> D5 C © 

tjh w t>; os © 

CO CO cd co" J>* 



CO CO W CI OS 
CXI CO W t>; CO 
t-" t>* l>* l>* l>* 



CO CO o t^ w 
q cxi tjh w t>- 

CO* CO* CO* co" CO* 



r-l CO W t>- OS 

co os q r-j cxj 


<M rfl CO OS Cq 
-^ w CO t>- OS 


■* t> O CO (D 
O r-j CO TtJ w 


tj* Tj" w* w" w* 


w* w* w* w* w* 


CO CO CO* co" CO* 



CO 


CI 

cc 


CO 
CO 


-* 
cc 


w 

CD 


CO 
CO 


cc 


00 
CO 


OS 
CO 


o 


i— i 
i>- 


CJ 


eo 
i> 




w 


© 


d 


d 


d 


d 


d 


d 


d 


d 


d 


d 


d 


d 


d 


d 



Bulletin 247 irrigation MEASURING DEVICES 139 



Bill of Material for Cipolletti Weir Box 

The bill of material given below covers what is necessary for an 
18-inch Cipolletti weir box and weir as installed at Davis. This box 
is long enough and of such other dimensions as to meet the general 
conditions that have been named. In some situations the box might 
be made somewhat shorter, but the additional cost required for a 12- 
foot over, say, an 8-foot box is not sufficient to justify using the 
shorter box where only a small number of weirs are involved. This 
box is suitable for measuring from about 0.25 to about 1.75 or 2 cubic 
feet per second, equivalent to 12% to 100 customary California miner's 
inches. 



Bill of Material for Cipolletti Weir Box 

Board feet 

4 pc. 1" X12" X 2' (cut-off walls) 8 

1 pc. 1" X 12" X 7' (cut-off walls) 7 

4 pc. 1" X 12" X 12' (main walls) 48 

7 pc. 1" X 12" X 12' (floor) 84 

8 pc. 2" X 4" X 3' (posts) 16 

2 pc. 4" X 4" X 4'-4" (posts) 12 

8 pc. 1" X 2" X 2' (cleats) 3 

1 pc. 2" X 4" X 4'-6" (gate stem) 3 

1 pc. 2" X 2" X 6' (gate stem brace) ,. 2 

2 pc. 2" X 12" X 3' (gate) 12 

2 pc. 2" X 12" X 3' (weir board) 12 

8 pc. 2" X 4" X 3'-10" (caps and sills) 21 

Total 228 



Weir Without End Contractions 

This is illustrated by Figure 14, which is from a photograph of the 
weir of this type installed at Davis. It is different from the Cipolletti 
weir just described mainly in having the weir board extend the full 
width of the weir box. The same bill of material can therefore be 
used except that more or less lumber will be necessary according to 
the width and height of the weir chosen. This type of weir can onh 
be used in a channel of constant cross-section and vertical sides directly 



140 



UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 



above the weir, such as is provided in the box shown. This weir must 
be so constructed as to allow free access of air to the under side of the 

falling sheet of water. This can 
be accomplished by making a hori- 
zontal notch in the side of the weir 
box directly below the crest and 
extending down stream to the end 
of the wall. The water must not 
be allowed to approach the weir 
with an appreciable velocity. The 
velocity of approach is largely gov- 
erned by the height of the weir 
board above the bottom of the box. 
It has been suggested by Professor 
Richard R. Lyman," of the Univer- 
sity of Utah, that a weir of this 
type 1 foot or less long should be 
6 inches high, that with lengths of 
1 .5 to 2.5 feet, it should be 9 inches 
high, that with lengths of 3 to 4 
feet it should be 1 foot high, and 
that with lengths of 5 to 7 feet it 




Fig. 14. — Photograph of weir without 
end contractions 



should be 1.5 feet high. In the same bulletin Professor Lyman gives 
the following table of discharges per foot of length for such a weir.f 







Ti 


\BLE 3 






Discharge of 


Weirs W 


[thout End 


Contractions in Cubic Feet 


per Sec 


Head in 
inches 


Head 
in feet 


Weir 

0.5 ft. 
high 


Weir 

0.75 ft. 

high 


Weir 

1.00 ft. 

high 


Weir 

1.50 ft 
high 


2% 


0.200 


0.315 


0.314 


0.313 


0.312 


2 7 /l6 


0.205 


0.327 


0.326 


0.325 


0.324 


2i/, 


0.210 


0.340 


0.337 


0.336 


0.335 


2% G 


0.215 


0.352 


0.351 


0.350 


0.348 


2% 


0.220 


0.365 


0.363 


0.360 


0.359 


2% 


0.225 


0.377 


0.375 


0.372 


0.370 


2% 


0.230 


0.392 


0.388 


0.385 


0.383 


21%, 


0.235 


0.404 


0.400 


0.398 


0.396 


2% 


0.240 


0.420 


0.415 


0.412 


0.408 


2i% 6 


0.245 


0.433 


0.427 


0.425 


0.422 



* Utah Engineering Experiment Station, Bull. 5. 

t The tables given in the bulletin referred to cover depths for weirs up to 6 
feet high. 



Bulletin 247 IRRIGATION MEASURING DEVICES 141 

TABLE 3 — (Continued) 

Discharge of Weirs Without End Contractions in Cubic Feet per Second 



Head in 
inches 


Head 
in feet 


Weir 
0.5 ft. 
high 


Weir 

0.75 ft. 

high 


Weir 

1.00 ft. 

high 


Weir 

1.50 ft. 

high 


3 


0.250 


0.446 


0.442 


0.438 


0.435 


3% 6 


0.255 


0.460 


0.453 


0.450 


0.447 


3% 


0.260 


0.475 


0.468 


0.465 


0.460 


3 3 /l6 


0.265 


0.490 


0.483 


0.478 


0.475 


3% 


0.270 


0.503 


0.497 


0.493 


0.488 


3%g 


0.275 


0.515 


0.508 


0.505 


0.501 


3% 


0.280 


0.530 


0.524 


0.518 


0.514 


3 7 /l6 


0.285 


0.546 


0.537 


0.532 


0.526 


3y 2 


0.290 


0.560 


0.552 


0.547 


0.544 


3 9 /i 6 


0.295 


0.576 


0.566 


0.560 


0.555 


3% 


0.300 


0.595 


0.584 


0.576 


0.570 


3% 


0.305 


0.610 


0.595 


0.588 


0.582 


3% 


0.310 


0.625 


0.612 


0.605 


0.59.. 


3% 


0.315 


0.640 


0.627 


0.620 


0.613 


3i3/ 16 


0.320 


0.655 


0.645 


0.636 


0.630 


3% 


0.325 


0.670 


0.655 


0.650 


0.641 


3% 


0.330 


0.690 


0.672 


0.665 


0.656 


4 


0.335 


0.705 


0.690 


0.680 


0.670 


4^6 


0.340 


0.720 


0.705 


0.697 


0.688 


4y 8 


0.345 


0.738 


0.720 


0.710 


0.703 


4 3 /i 6 


0.350 


0.755 


0.735 


0.726 


0.717 


4% 


0.355 


0.770 


0.752 


0.743 


0,732 


4% 6 


0.360 


0.790 


0.772 


0.760 


0.750 


4% 


0.365 


0.805 


0.786 


0.775 


0.764 


4% 6 


0.370 


0.824 


0.802 


0.792 


0.780 


4y 2 


0.375 


0.840 


0.817 


0.805 


0.795 


4%6 


0.380 


0.860 


0.836 


0.825 


0.813 


4% 


0.385 


0.875 


0.853 


0.840 


0.826 


4% 


0.390 


0.896 


0.870 


0.857 


0.845 


4% 


0.395 


0.910 


0.885 


0.870 


0.860 


4 13 /ie 


0.400 


0.930 


0.905 


0.893 


0.875 


m 


0.405 


0.950 


0.922 


0.910 


0.895 


4 15 /l6 


0.410 


0.970 


0.940 


0.925 


0.910 


5 


0.415 


0.990 


0.956 


0.943 


0.925 


5^L6 


0.420 


1.005 


0.975 


0.958 


0.943 


5y 8 


0.425 


1.020 


0.995 


0.977 


0.963 


5y 8 


0.430 


1.045 


1.010 


0.996 


0.980 


5% 6 


0.435 


1.065 


1.030 


1.010 


0.996 


51/4 


0.440 


1.083 


1.045 


1.026 


1.010 


5-Yio 


0.445 


1.100 


1.063 


1.045 


1.026 



142 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 

TABLE 3— (Continued) 
Discharge of Weirs Without End Contractions in Cubic Feet per Second 







Weir 


Weir 


Weir 


Weir 


Head in 


Head 


0.5 ft. 


0.75 ft. 


1.00 ft. 


1.50 ft. 


inches 


in feet 


high 


high 


high 


high 


5% 


0.450 


1.120 


1.080 


1.060 


1.040 


57/16 


0.455 


1.140 


1.100 


1.080 


1.057 


5Vo 


0.460 


1.164 


1.125 


1.105 


1.085 


5%6 


0.465 


1.185 


1.140 


1.120 


1.100 


5% 


0.470 


1.205 


1.163 


1.143 


1.120 


511/ig 


0.475 


1.230 


1.185 


1.162 


1.140 


5% 


0.480 


1.250 


1.205 


1.185 


1.160 


5% 


0.485 


1.270 


1.223 


1.200 


1.175 


5% 


0.490 


1.290 


1.245 


1.220 


1.200 


515/ 16 


0.495 


1.310 


1.265 


1.233 


1.215 


6 


0.500 


1.335 


1.285 


1.263 


1.235 


6I/16 


0.505 


1.355 


1.300 


1.280 


1.250 


ey 8 


0.510 


1370 


1.320 


1.296 


1.270 


6% 6 


0.515 


1.390 


1.340 


1.317 


1.287 


6 y 4 


0.520 


1.415 


1.360 


1.335 


1.305 


65/16 


0.525 


1.440 


1.380 


1.355 


1.325 


6% 


0.530 


1.465 


1.405 


1.375 


1.346 


6 7 /l6 


0.535 


1.490 


1.425 


1.400 


1.365 


ey 2 


0.540 


1.510 


1.440 


1.415 


1.385 


6%6 


0.545 


1.530 


1.465 


1.435 


1.403 


6% 6 


0.550 


1.555 


1.490 


1.460 


1.425 


6% 


0.555 


1.575 


1.505 


1.475 


1.440 


6% 


0.560 


1.595 


1.525 


1.495 


1.460 


6% 


0.565 


1.616 


1.545 


1.515 


1.475 


613/ 16 


0.570 


1.640 


1.570 


1.535 


1.500 


6% 


0.575 


1.665 


1.590 


1.555 


1.517 


6i5/ 16 


0.580 


1.686 


1.610 


1.576 


1.537 


7 


0.585 


1.713 


1.635 


1.605 


1.565 


7% 6 


0.590 


1.740 


1.670 


1.630 


1.590 


7y 8 


0.595 


1.760 


1.685 


1.650 


1.605 


7% 6 


0.600 


1.790 


1.700 


1.675 


1.625 


7% 


0.605 


1.805 


1.730 


1.695 


1.655 


7^6 


0.610 


1.830 


1.750 


1.715 


1.675 


7% 


0.615 


1.855 


1.755 


1.735 


1.695 


7 7 /l6 


0.620 


1.880 


1.795 


1.760 


1.710 


7y 2 


0.625 


1.905 


1.815 


1.780 


1.730 


7 9 / 6 


0.630 


1.930 


1.845 


1.805 


1.760 


7% 


0.635 


1.955 


1.875 


1.835 


1.785 


7 n /i6 


0.640 


1.980 


1.900 


1.860 


1.815 


7% 


0.645 


2.010 


1.915 


1.870 


1.820 



Bulletin 247 



IRRIGATION MEASURING DEVICES 



143 



TABLE 3— {Continued) 
Discharge of Weirs Without End Contractions in Cubic Feet per Second 



Head in 
inches 


Head 
in feet 


Weir 
0.5 ft. 
high 


Weir 

0.75 ft. 

high 


Weir 

1.00 ft. 

high 


Weir 

1.50 ft. 

high 


WIG 


0.650 


2.035 


1.930 


1.890 


1.840 


f% 


0.655 


2.060 


1.960 


1.915 


1.860 


7 15 /l6 


0.660 


2.085 


1.985 


1.945 


1.890 


8 


0.665 


2.110 


2.005 


1.965 


1.910 


% 


0.670 


2.135 


2.025 


1.980 


1.930 


% 


0.675 


2.160 


2.055 


2.000 


1.945 


sy 8 


0.680 


2.185 


2.075 


2.030 


1.980 


8 3 /l6 


0.685 


2.210 


2.095 


2.050 


1.990 


8% 


0.690 


2.240 


2.125 


2.075 


2.025 


8 5 /l6 


0.695 


2.260 


2.150 


2.095 


2.040 


8% 


0.700 


2.295 


2.180 


2.130 


2.070 


8 7 /l6 


0.705 


2.325 


2.200 


2.155 


2.100 


8% 


0.710 


2.350 


2.220 


2.170 


1.115 


8%6 


0.715 


2.380 


2.250 


2.195 


2.140 


8% 


0.720 


2.410 


2.275 


2.220 


2.160 


SH/ie 


0.725 


2.435 


2.300 


2.245 


2.180 


8% 


0.730 


2.465 


2.325 


2.270 


2.200 


81%, 


0.735 


2.490 


2.350 


2.295 


2.230 


8% 


0.740 


2.520 


2.375 


2.32u 


2.250 


81%, 


0.745 


2.550 


2.405 


2.340 


2.275 


9 


0.750 


2.585 


2.430 


2.375 


2.300 


% 


0.755 


2.605 


2.455 


2.400 


2.325 


9y 8 


0.760 


2.640 


2.480 


2.415 


2.340 


9 3 /l6 


0.765 


2.670 


2.510 


2.440 


2.370 


9V 4 


0.770 


2.700 


2.540 


2.470 


2.400 


9%6 


0.775 


2.730 


2.560 


2.500 


2.420 


9% 


0.780 


2.760 


2.590 


2.515 


2.440 


9%6 


0.785 


2.790 


2.610 


2.550 


2.460 


9y 2 


0.790 


2.820 


2.630 


2.570 


2.480 


9%6 


0.795 


2.850 


2.660 


2.595 


2.510 


9%6 


0.800 


2.890 


2.700 


2.625 


2.550 


9% 


0.805 


2.910 


2.730 


2.660 


2.575 


9U/16 


0.810 


2.940 


2.755 


2.680 


2.595 


9% 


0.815 


2.975 


2.780 


2.700 


2.610 


9i% 6 


0.820 


3.010 


2.810 


2.735 


2.640 


9y s 


0.825 


3.045 


2.840 


2.770 


2.670 


9 15 /l6 


0.830 


3.070 


2.870 


2.790 


2.700 


10 


0.835 


3.100 


2.905 


2.830 


2.730 


lOile 


0.840 


3.130 


2.930 


2.840 


2.760 


ioy 8 


0.845 


3.160 


2.950 


2.880 


2.785 



144 



UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 



TABLE 3— (Continued) 
Discharge of Weirs Without End Contractions in Cubic Feet per Second 







Weir 


Weir 


Weir 


Weir 


Head in 


Head 


0.5 ft. 


0.75 ft. 


1.00 ft. 


1.50 ft. 


inches 


in feet 


high 


high 


high 


high 


10% 6 


0.850 


3.190 


2.990 


2.910 


2.800 


10% 


O.8O0 


3.230 


3.015 


2.930 


2.840 


105/i 6 


0.860 


3.260 


3.040 


2.960 


2.860 


10% 


0.865 


3.290 


3.070 


2.980 


2.880 


1^ 6 


0.8/0 


3.320 


3.100 


3.010 


2.910 


10% 


0.875 


3.350 


3.120 


3.035 


2.930 


10%6 


0.880 


3.395 


3.160 


3.070 


2.965 


10% 


0.885 


3.415 


3.180 


3.090 


2.980 


1011/16 


0.890 


3.445 


3.200 


3.120 


3.010 


10% 


0.985 


3.480 


3.235 


3.150 


3.040 


101%, 


0.900 


3.520 


3.270 


3.180 


3.070 


10% 


0.905 


3.550 


3.300 


3.210 


3.100 


10% 


0.910 


3.580 


3.330 


3.235 


3.120 


11 


0.915 


3.620 


3.360 


3.260 


3.155 


llVio 


0.920 


3.655 


3.390 


3.290 


3.180 


11% 


0.925 


3.690 


3.420 


3.325 


3.210 


11% 


0.930 


3.720 


3.445 


3.350 


3.230 


H 3 /lG 


0.935 


3.760 


3.480 


3.380 


3.250 


11% 


0.940 


3.800 


3.510 


3.405 


3.290 


H 5 /l6 


0.945 


3.830 


3.540 


3.430 


3.315 


11% 


0.950 


3.870 


3.580 


3.470 


3.350 


11%6 


0.955 


3.900 


3.610 


3.500 


3.380 


ny 2 


0.960 


3.940 


3.640 


3.540 


3.400 


ii% 6 


0.965 


3.980 


3.680 


3.570 


3.430 


n% 


0.970 


4.010 


3.700 


3.590 


3.450 


H ll /lG 


0.975 


4.040 


3.740 


3.625 


3.490 


11% 


0.980 


4.080 


3.770 


3.650 


3.520 


1H3/ 16 


0.985 


4.120 


3.800 


3.690 


3.555 


H 7 /s 


0.990 


4.150 


3.830 


3.710 


3.580 


1115/ 16 


0.995 


4.180 


3.850 


3.730 


3.590 


12 


1.000 


4.230 


3.900 


3.780 


3.640 


12% 


1.010 


4.300 


3.970 


3.840 


3.710 


121/i 


1.020 


4.380 


4.030 


3.900 


3.760 


12% 


1.030 


4.450 


4.100 


3.970 


3.820 


121/2 


1.040 


4.520 


4.170 


4.040 


3.880 


12% 


1.050 


4.610 


4.240 


4.120 


3.950 


12H/ 16 


1.060 


4.800 


4.320 


4.180 


4.020 


12i% 6 


1.070 


4.760 


4.370 


4.220 


4.070 


1215/ 16 


1.080 


4.820 


4.430 


4.280 


4.130 


13Me 


1.090 


4.900 


4.480 


4.340 


4.180 



Bulletin 24' 



IRRIGATION MEASURING DEVICES 



145 



TABLE 3— (Continued) 
Discharge of Weirs Without End Contractions in Cubic Feet per Second 

Weir Weir Weir Weir 

Head in Head 0.5 ft. 0.75 ft. 1.00 ft. 1.50 ft. 

inches in feet high high high high 

13% 6 1.100 . 4.980 4.570 4.420 4.240 

13% 6 1.110 5.060 4.640 4.480 4.320 

13% 6 1.120 5.150 4.710 4.560 4.370 

13% 6 1.130 5.220 4.780 4.610 4.420 

13% 1.140 5.300 4.840 4.670 4.480 

131%; 1.150 5.380 4.910 4.740 4.560 

13% 1.160 5.450 4.980 4.800 4.610 

14i/ 1G 1.170 5.510 5.050 4.870 4.670 

14% 1.180 5.600 5.130 4.950 4.740 

14% 1.190 5.680 5.200 5.000 4.800 

14% 1.200 5.780 5.250 5.075 4.870 

14% 1.210 5.860 5.340 5.150 4.940 

14% 1.220 5.940 5.420 5.250 5.000 

14% 1.230 6.000 5.460 5.270 5.050 

14% 1.240 6.100 5.550 5.360 5.150 

15 1.250 6.200 5.620 5.430 5.220 

15% 1.260 6.275 5.675 5.500 5.275 

15% 1.270 5.750 5.560 5.325 

15% 1.280 5.820 5.620 5.380 

15% 1.290 5.900 5.680 5.450 

15% 1.300 5.975 5.775 5.525 

15% 1.310 6.060 5.850 5.600 

15uy 1(; 1.320 6.150 5.920 5.675 

15% 1.330 6.200 6.000 5.730 

16140" 1.340 . ... 6.300 6.050 5.800 

16% G 1.350 6.375 6.130 5.875 

165/ie 1.360 6.450 6.200 5.940 

16vle i- 370 6 - 505 6 - 300 6 - 000 

16% G 1.380 6.625 6.375 6.080 

16%, 1.390 6.700 6.459 6.150 

16% 1.400 6.780 6.530 6.230 

16% 1.410 - 6.860 6.620 6.320 

17i/ 16 * 1.420 6.950 6.675 6.375 

17% 1.430 7.000 6.750 6.450 

17% 1.440 7.075 6.820 6.520 

17% 1.450 7.150 6.900 6.600 

17% 1.460 7.250 6.975 6.660 

17% 1.470 7.330 7.050 6.740 

17% 1.480 - 7.400 7.130 6.800 

17% 1.490 7.480 7.200 6.850 



146 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 

TABLE 3— (Concluded) 
Discharge of Weirs Without End Contractions in Cubic Feet per Second 

Weir Weir Weir Weir 

Head in Head 0.5 ft, 0.75 ft. 1.00 ft. 1.50 ft. 

inches in feet high high high high 

18 1.500 7.600 -7.300 6.950 

18% 1.510 7.660 7.360 7.020 

18% 1.520 7.750 7.450 7.100 

18% 3.530 7.825 7.520 7.160 

18% 1.540 7.900 7.600 7.230 

18% 1.550 7.980 7.660 7.300 

18H/ 16 1.560 8.075 7.730 7.400 

18i% 6 1.570 8.150 7.820 7.450 

1815/ 16 1.580 8.250 7.900 7.525 

19i/ 1G 1.590 8.300 7.960 7.560 



SUBMERGED ORIFICES 

The measurement of water through orifices has long been common 
in irrigation practice and various forms of orifices have been devel- 
oped. The essential condition in the use of an orifice, eliminating the 
question of form, is that the water on the up-stream side of the orifice 
shall completely submerge it. If, when in use, the surface of the water 
on the lower side of the orifice is below the bottom thereof, the orifice 
is said to have a free discharge. If the surface of the water on the 
lower side of the orifice is above the top of the orifice, completely sub- 
merging it, it is classed as a submerged orifice. Except in the case 
of the miner's inch box, which is really but a form of orifice with free 
discharge, use of the orifice in irrigation practice is confined to the 
submerged form. 

Submerged orifices as used can be divided into two general types, 
viz : those with orifices of fixed dimensions (Figs. 15 and 16) and those 
built so that the height of the opening may be varied (Figs. 17 and 18) . 
Orifices with fixed dimensions are usually made with sharp edges 
similar to the crest of a weir. The most usual type of the second class 
is the simple head gate (Figs. 17 and 18), which is also used as a 
submerged orifice, the height of opening and loss of head being ad- 
justed to the amount which it is desired to turn out and to the loss of 
head available. Of these two types, the sharp-edged orifice with fixed 
dimensions is much the more accurate. 



Bulletin 247 



IRRIGATION MEASURING DEVICES 



147 



SUBMERGED ORIFICES WITH FIXED DIMENSIONS 

This type of submerged orifice is used for measurement only, the 
fixing of the size of the opening preventing its use as a headgate. 
The experiments which have been made by hydraulic engineers to de- 
termine the coefficient of discharge for the standard sharp-edged orifice 




Fig. 15. — Drawing of submerged orifice used by U. S. Reclamation Service 



approach in accuracy and number those that have been made for 
sharp-edged weirs. These experiments have shown the coefficients to 
vary slightly with the size of the orifice. For the sizes used in the 
measurement of individual deliveries of irrigation water this variation 
may be overlooked and one formula used for all sizes. 

In order that the known formula for the discharge through such 
orifices shall apply, certain standard conditions must be observed in 
the construction and use of these orifices. The edges of the orifice must 



148 



UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 



be sharp and definite in shape. It is preferable to use a thin metal 
plate as this is not subject to wear and change. The edges of the 
orifice should not be too near to the sides of the box on either the upper 
or lower sides; a distance equal to twice the least dimension of the 
orifice is sufficient. The orifice should be vertical with the top and 
bottom edges level. The ditch above the orifice should be sufficiently 
large so that the velocity of approach will be small, as is necessary in 
the case of a weir. Corrections can be made in the computations for 
any velocity of approach but such corrections are more or less un- 
certain. 




Fig. 16. — Photograph of submerged orifice used by U. S. Reclamation Ser 



The principal sources of error in measurements with this type of 
orifice are due to errors in the gage readings to determine the difference 
in the elevation of the water on the two sides, this being the head or 
pressure that forces the water through the orifice. As these orifices 
are generally used where there is but little loss of head available, the 
opening is usually made sufficiently large to require as little loss of 
head as is practicable. Any error in reading this loss of head is thus 
a larger percentage of the whole than it would be for greater total 
differences. 

In the use of the submerged orifice two gage readings are required, 
one above and one below the orifice. The reading above the orifice 
should be taken back from the edge of the orifice. In the type of struc- 
ture shown in figures 13 and 14 this can be taken on the side wing wall. 



Bulletin 247 



IRRIGATION MEASURING DEVICES 



149 



The measurement below the orifice should be taken at least 2 feet below 
it and farther if the discharging- water is rough. A convenient method 
of obtaining the difference in the elevation of the water above and 
below the orifice is to set marks at equal elevations above and below 
the orifice or to set a board with its top level extending above and 
below the orifice sufficiently far to give good points for measurements. 
The difference in measurements from this level board to the surface of 
the water above and below the orifice gives the head or pressure under 
which the water is passing through the orifice. 

The type of orifice described above and illustrated in figures 13 and 
14 has been adopted by the U. S. Eeclamation Service for use where 
sufficient loss of head is not available for weirs. The data given below 
regarding the sizes of the structures, and the table of discharges 
(Table 4) are taken from the publication of the Reclamation Service 
on the measurement of irrigation water and from their standard plans 
for submerged orifices. The cost of one of these devices installed will 
vary from about $5 to about $15. 



Dimensions and Lumber for Standard Sizes of Submerged Rectangular 
Orifices Adopted by U. S. Reclamation Service 





Size of Orifice 

A 




Headwall 

height 

in ft. 

b 


Side 

height 

in ft. 

c 


Structure 

length 

in ft. 

d 


Floor 

width 

in ft. 

e 


Approxi- 
mate 
quantity 
of lumber 
in ft. B.M 


height 

in ft. 

f 


Length 

in ft. 

a 


Area 

in 
sq. ft. 




r i.oo 


0.25 


3.0 


2.5 


4.0 


2.0 


150 


0.25 


J 2.00 


0.50 


3.0 


2.5 


4.0 


3.0 


170 




1 3.00 


0.75 


3.0 


2.5 


4.0 


4.0 


185 






r 1.00 


0.50 


3.0 


2.5 


4.0 


2.0 


150 






1.50 


0.75 


3.0 


2.5 


4.0 


2.5 


160 


0.50 


" 


2.00 


1.00 


3.0 


2.5 


4.0 


3.0 


170 






2.50 


1.25 


3.0 


2.5 


4.0 


3.5 


175 






3.00 


1.50 


3.5 


2.5 


4.0 


4.0 


210 






r 1.33 


1.00 


3.0 


2.5 


4.0 


2.0 


150 






1.67 


1.25 


3.0 


2.5 


4.0 


2.5 


160 


0.75 


< 


2.00 


1.50 


3.0 


2.5 


4.0 


3.0 


170 






2.33 


1.75 


3.5 


3.0 


4.0 


3.0 


190 






2.67 


2.00 


3.5 


3.0 


4.0 


3.5 


200 



150 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 



TABLE 4 

Discharge of Submerged Eectangular Orifices in Cubic Feet per Second. 

Computed from the Formula Q = 0.61 V2gH A — Taken from 

' ' Measurement of Irrigation Water ' ' Tables of 

U. S. Reclamation Service 



H, 






Cross-sectional area 


A of orifice, 


square feet 






feet 


0.25 


0.5 


0.75 


1.0 


1.25 


1.5 


1.75 


2.00 


0.01 


0.122 


0.24o 


0.367 


0.489 


0.611 


0.734 


0.856 


0.978 


.02 


.173 


.346 


.518 


.691 


.864 


1.037 


1.210 


1.382 


.03 


.212 


.424 


.635 


.847 


1.059 


1.271 


1.483 


1.694 


.04 


.245 


.489 


.734 


.978 


1.223 


1.468 


1.712 


1.957 


.05 


.273 


.547 


.820 


1.093 


1.367 


1.640 


1.913 


2.186 


.06 


.300 


.599 


.899 


1.198 


1.497 


1.797 


2.097 


2.396 


.07 


.324 


.647 


.971 


1.294 


1.617 


1.941 


2.265 


2.588 


.08 


.346 


.691 


1.03; 


1.383 


1.729 


2.074 


2.420 


2.766 


.09 


.367 


.734 


1.101 


1.468 


1.835 


2.201 


2.638 


2.935 


.10 


.387 


.773 


1.160 


1.557 


1.933 


2.320 


2.707 


3.094 


.11 


.406 


.811 


1.217 


1.622 


2.027 


2.433 


2.839 


3.244 


.12 


.424 


.847 


1.271 


1.694 


2.118 


2.542 


2.965 


3.389 


.13 


.441 


.882 


1.323 


1.764 


2.205 


2.645 


3.086 


3.527 


.14 


.458 


.915 


1.373 


1.830 


2.287 


2.745 


3.203 


3.660 


.15 


.474 


.947 


1.421 


1.895 


2.369 


2.842 


3.316 


3.790 


.16 


.489 


.978 


1.467 


1.956 


2.445 


2.934 


3.423 


3.912 


.17 


.504 


1.008 


1.512 


2.016 


2.520 


3.024 


3.528 


4.032 


.18 


.519 


1.037 


1.556 


2.075 


2.593 


3.112 


3.631 


4.150 


.19 


.533 


1.066 


1.599 


2.132 


2.665 


3.198 


3.731 


4.264 


.20 


.547 


1.094 


1.641 


2.188 


2.735 


3.282 


3.829 


4.376 


.21 


.561 


1.120 


1.681 


2.241 


2.801 


3.361 


3.921 


4.482 


.22 


.574 


1.148 


1.722 


2.296 


2.870 


3.464 


4.018 


4.592 


.23 


.587 


1.172 


1.7o9 


2.345 


2.931 


3.517 


4.103 


4.690 


.24 


.600 


1.198 


1.797 


2.396 


2.995 


3.599 


4.193 


4.792 


.25 


.612 


1.223 


1.834 


2.446 


3.057 


3.668 


4.280 


4.891 


.26 


.624 


1.247 


1.871 


2.494 


3.117 


3.741 


4.365 


4.988 


.27 


.636 


1.270 


1.906 


2.541 


3.176 


3.811 


4.446 


5.082 


.28 


.646 


1.294 


1.942 


2.589 


3.236 


3.883 


4.530 


5.178 


.29 


.659 


1.319 


1.978 


2.638 


3.297 


3.956 


4.616 


5.276 


.30 


.670 


1.339 


2.009 


2.678 


3.347 


4.017 


4.687 


5.356 


.31 


.681 


1.363 


2.045 


2.726 


3.407 


4.089 


4.771 


5.452 


.32 


.692 


1.382 


2.073 


2.764 


3.455 


4.146 


4.837 


5.528 


.33 


.703 


1.405 


2.107 


2.810 


3.513 


4.215 


4.917 


5.620 


.34 


.713 


1.426 


2.139 


2.852 


3.565 


4.278 


4.991 


5.704 


.35 


.724 


1.446 


2.169 


2.892 


3.615 


4.338 


5.061 


5.784 



Bulletin 247 IRRIGATION MEASURING DEVICES 151 

TABLE 4— (Continued) 

Discharge of Submerged Rectangular Orifices in Cubic Feet per Second, 

Computed from the Formula Q = 0.6-l V^gH A — Taken from 

' ' Measurement of Irrigation Water ' ' Tables of 

U. S. Reclamation Service 



H, 






Cross-sectional area 


A of orifice, 


square feet 






feet 


0.25 


0.5 


0.75 


1.0 


1.25 


1.5 


1.75 


2.00 


.36 


.734 


1.467 


2.201 


2.934 


3.667 


4.401 


5.135 


5.868 


.37 


.745 


1.488 


2.232 


2.976 


3.720 


4.464 


5.208 


5.952 


.38 


.754 


1.508 


2.262 


3.016 


3.770 


4.524 


5.278 


6.032 


.39 


.764 


1.527 


2.291 


3.054 


3.818 


4.582 


5.345 


6.109 


.40 


.774 


1.547 


2.321 


3.094 


3.867 


4.641 


5.415 


6.188 


.41 


.783 


1.567 


2.350 


3.133 


3.917 


4.700 


5.483 


6.266 


.42 


.792 


1.585 


2.377 


3.170 


3.962 


4.754 


5.547 


6.339 


.43 


.802 


1.604 


2.406 


3.208 


4.010 


4.812 


5.614 


6.416 


.44 


.811 


1.622 


2.433 


3.244 


4.055 


4.866 


5.677 


6.488 


.45 


.820 


1.640 


2.461 


3.281 


4.101 


4.921 


5.741 


6.562 


.46 


.829 


1.659 


2.489 


3.318 


4.147 


4.977 


5.807 


6.636 


.47 


.839 


1.678 


2.517 


3.356 


4.195 


5.035 


5.874 


6.713 


.48 


.847 


1.695 


2.542 


3.389 


4.237 


O.084 


5.931 


6.778 


.49 


.856 


1.712 


2.568 


3.424 


4.280 


5.136 


5.992 


6.848 


.50 


.865 


1.729 


2.594 


3.458 


4.323 


5.188 


6.052 


6.917 


.51 


.873 


1.746 


2.620 


3.493 


4.366 


5.239 


6.112 


6.986 


.52 


.882 


1.763 


2.645 


3.527 


4.409 


5.290 


6.172 


7.054 


.53 


.890 


1.780 


2.670 


3.560 


4.451 


5.341 


6.231 


7.121 


.54 


.898 


1.797 


2.695 


3.593 


4.491 


5.390 


6.288 


7.186 


.55 


.907 


1.813 


2.719 


3.626 


4.533 


5.439 


6.345 


7.252 


.56 


.915 


1.830 


2.745 


3.660 


4.575 


5.490 


6.405 


7.320 


.57 


.923 


1.846 


2.769 


3.692 


4.615 


5.538 


6.461 


7.384 


.58 


.931 


1.862 


2.794 


3.725 


4.656 


5.587 


6.518 


7.450 


.59 


.939 


1.879 


2.818 


3.757 


4.697 


5.636 


6.575 


7.514 


.60 


.947 


1.895 


2.842 


3.790 


4.737 


5.684 


6.632 


7.579 


.61 


.955 


1.910 


2.865 


3.820 


4.775 


5.730 


6.685 


7.640 


.62 


.963 


1.925 


2.887 


3.850 


4.812 


5.775 


6.737 


7.700 


.63 


.971 


1.941 


2.911 


3.882 


4.853 


5.823 


6.793 


7.764 


.64 


.978 


1.956 


2.934 


3.912 


4.890 


5.868 


6.846 


7.824 


.65 


.986 


1.972 


2.958 


3.944 


4.930 


5.916 


6.902 


7.888 


.66 


.993 


1.987 


2.980 


3.974 


4.967 


5.960 


6.954 


7.947 


.67 


1.001 


2.002 


3.003 


4.004 


5.005 


6.006 


7.007 


8.008 


.68 


1.008 


2.016 


3.024 


4.032 


5.040 


6.048 


7.056 


8.064 


.69 


1.016 


2.032 


3.048 


4.064 


5.080 


6.096 


7.112 


8.128 


.70 


1.023 


2.046 


3.069 


4.092 


5.115 


6.138 


7.161 


8.184 



152 



UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 



TABLE 4— (Concluded) 

Discharge of Submerged Eectangular Orifices in Cubic Feet per Second, 

Computed from the Formula Q = 0.61 V2gH A — Taken from 

' ' Measurement of Irrigation Water ' ' Tables of 

U. S. Reclamation Service 



H, 






Cross-sect 


lonal area A of orifice, 


square feet 






feet 


0.25 


0.5 


0.75 


1.0 


1.25 


1.5 


1.75 


2.00 


.71 


1.031 


2.062 


3.093 


4.124 


5.155 


6.186 


7.217 


8.248 


.72 


1.038 


2.076 


3.114 


4.152 


5.190 


6.228 


7.266 


8.304 


.73 


1.045 


2.090 


3.135 


4.180 


5.225 


6.270 


7.315 


8.360 


.74 


1.052 


2.104 


3.158 


4.210 


5.260 


6.311 


7.369 


8.421 


.75 


1.059 


2.118 


3.178 


4.237 


5.296 


6.355 


7.413 


8.475 


.76 


1.066 


2.132 


3.198 


4.264 


5.330 


6.396 


7.462 


8.528 


.77 


1.072 


2.145 


3.217 


4.290 


5.362 


6.434 


7.507 


8.579 


.78 


1.080 


2.160 


3.240 


4.320 


5.400 


6.480 


7.560 


8.640 


.79 


1.087 


2.174 


3.261 


4.348 


5.435 


6.522 


7.609 


8.696 


.80 


1.094 


2.188 


3.282 


4.376 


5.470 


6.564 


7.658 


8.752 



TABLE 5 

Coefficient C to be Applied to a Discharge Given by Table 3 to Give the 
Discharge of the Same Orifice Suppressed, Computed from the Formula 
C — 1 + 0.15 r, Where r = Ratio of the Suppressed Portion of the 
Perimeter of the Orifice to the Whole Perimeter. Takex b'rom 
il Measurement of Irrigation Water" by U. S. Reclamation Service. 



d.feet 



0.25 



0.5 



0.75 



Size of orifice 
t 1, feet 


A, 
square feet 


Bottom 


suppressed 
C 


Bottom and sides 
suppressed 

r C 


r i.o 


0.25 


0.40 


1.06 


0.60 


1.09 


J 2.0 


.50 


.44 


1.07 


.56 


1.08 


3.0 


.75 


.46 


1.07 


.54 


1.08 




' 1.0 


.50 


.33 


1.05 


.67 


1.10 




1.5 


.75 


.37 


1.06 


.63 


1.09 


■4 


2.0 


1.00 


.40 


1.06 


.60 


1.09 




2.5 


1.25 


.42 


1.06 


.58 


1.09 




3.0 


1.50 


.43 


1.06 


.57 


1.09 




r 1.33 


1.00 


.32 


1.05 


.68 


1.10 




1.67 


1.25 


.34 


1.05 


.66 


1.10 


-< 


2.00 


1.50 


.36 


1.05 


.64 


1.10 




2.33 


1.75 


.38 


1.06 


.62 


1.09 




2.67 


2.00 


.39 


1.06 


.61 


1.09 



Bulletin 24' 



IRRIGATION MEASURING DEVICES 



153 



One of the orifices described above, 2.0 feet wide and 0.5 foot high, 
has been installed at Davis and a series of tests made with discharges 
of from 1 to 2.2 cubic feet per second. The mean of all tests gave a 
coefficient for nse in the formula given with the table of 0.61, which is 
the same as has been found in other experiments. 

When properly installed this type of submerged orifice should give 
dependable results if the difference in head is correctly measured. 
Care should be taken to prevent silting in front of the orifice or the 
catching of drift. 



SUBMERGED ORIFICE HEADGATES 

This type of submerged orifice (Figs. 17 and 18) has been used to 
arge extent on systems where the small loss of head available makes 




17. — Drawing of submerged orifice headgate 



a combination of headgate and measuring device necessary. While 
all such devices have many points of similarity, different canal com- 
panies have adopted slightly different forms as their standard. 



154 



UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 



The accuracy of measurement of water through a submerged open- 
ing depends on the measurement of the loss of head, the area of the 
opening, and the selection of the coefficient for use in the formula of 
discharge. 

Measurements of the pressure for such gates are made in the same 
way as described for the submerged orifice with fixed opening. The 
best method is to make the measurements sufficiently far from the gate 
to avoid any sucking of the water on the upper side or rough water 
below. The pressure sometimes is determined by measuring down to 
the water surface on the upper and lower sides of the gate. This is a 
poor method as the water is liable to be drawn down below its true 
level above the gate and to shoot out from the gate below. The area 
of the opening is generally measured between a fixed mark on the gate 
stem and the top frame of the gate, the mark being placed so that it 
is even with the top of the frame when the gate is closed. The width 
is the same for any height of opening. 

The proper coefficient to use in computing the discharge through 
such orifices is uncertain. Within general limits for any fixed set of 
conditions, the coefficient is probably nearly constant, but the actual 
coefficient to use may depend on many variables. For this reason dis- 
charge tables are not included. The values for sharp-edged orifices 
0.61 or 0.62 have been used by some canal companies. It is certain 
that these values are too low for the orifices made of either 1-inch or 
2-inch lumber. The Yolo Water and Power Co. have adopted a 
standard form of headgate 3 feet wide with spreading wing walls, the 
bottom of the gate being 1 inch above the floor. Experiments made 
with this gate under the direction of Professor B. A. Etcheverry gave 

a mean value for the coefficient of 
0.73, which has been adopted by the 
company for use in the delivery of 
water. 

Tests of a submerged orifice gate 
under two conditions were made 
at Davis. One gate 3 feet wide 
with the bottom 6 inches above the 
floor were set at the upper end of 
the turnout box diverting from a 
concrete flume. This gate is similar 
in type to the one shown in Figure 
15. It was tested with discharges 
™ , „ , , of from 0.50 to 4.25 cubic feet 

-Photograph of submerged 
orifice headgate per second. The height of the side 




Fig. 18. 



Bulletin 247 IRRIGATION MEASURING DEVICES 155 

walls prevented the use of larger discharges, although the gate can 
handle much larger heads. The loss of head was determined by meas- 
uring down from a level board above and below the gate and also on 
the gate. The mean of all measurements using the level board gave 
a mean coefficient of 0.80 ; the measurements on the gate gave a mean 
of 0.72, but were more variable than the others. 

A similar gate set across the 3-foot wide concrete flume of the field 
laboratory was also tested, giving a mean value of 0.79 for the coeffi- 
cient with level board readings. The discharges varied from 1.6 to 6.9 
cubic feet per second in these experiments. 

From these results it is seen that the coefficient for such measuring 
gates varies with the type of gate. It is possible that the coefficient 
would have been lower for higher rates of discharge at Davis if such 
tests could have been made. 

There are several types of these gates in use in California. The 
gate used by Imperial Co. No. 1 is set 4 feet back from the front of 
the box. In the box used by the Kern County Land Co. the gate is 
set at the front, flush with the side of the canal. 

Where the lack of sufficient fall for the use of a better measuring 
device makes the use of this type of submerged orifice necessary, a 
standard size and structure should be adopted, and special discharge 
tables prepared. This should then be rated under the condition in 
which it will be used. As long as the conditions of use can be main- 
tained, fairly satisfactory measurements can be made. Care should 
be taken to prevent the deposit of silt or sand near the gate as this 
will change the conditions of discharge and affect the rating. The 
velocity above the gate should also be made as small as practicable. 

Bill of Material for Submerged Orifice Headgate 

Board feet 

12 pc. 2" X 12" X 2' (cut-off walls) 48 

2 pc. 2" X 12" X 6'-4" (cut-off walls) 26 

6 pc. 2" X 12" X 7'-4" (main walls) 88 

2 pc. 2" X 12" X 7'-4" (floor) 30 

1 pc. 2" X 4" X 7'-4" (floor) 8 

6 pc. 2" X 4" X 3'-10" (posts) 15 

4 pc. 2" X 4" X 4'-4" (posts) 12 

4 pc. 2" X 4" X 4'-4" (gate posts) 12 

3 pc. 2" X 4" X 3'-4" (caps) 7 

3 pc. 2" X 4" X 3'-4" (sills) 7 

2 pc. 2" X 4" X 2'-4" (gate caps) 3 

3 pc. 2" X 12" X 2'-4" (gate) 14 

1 pc. 1" X 6" X 7'-6" (gate stem) 4 

Total 274 



156 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 

The cost of one of these orifice headgates in Imperial Valley is 
given by the Superintendent of Mutual Water Company No. 1 as 
about $20. The items making up the total are, lumber about $9 ; labor, 
exclusive of excavation, about $8 ; excavation and incidentals, about $3. 

MECHANICAL DEVICES THAT MEASURE AND REGISTER 
THE TOTAL FLOW 

It is stated in the introduction of this bulletin that to be fully 
satisfactory for measuring individual deliveries of irrigation water 
a device should register the total amount of water passing, rather than 
the rate of flow. Three devices of this character — Dethridge, Grant- 
Mi chell, and Hill meters — have been installed at Davis and tested. A 
fourth, the Hanna meter, is to be installed as soon as available, only 
a photograph and brief description of it being included herein. 

DETHRIDGE METER 

This meter is shown in figures 19 and 20. It was invented by Mr. 
J. S. Dethridge, of the State Rivers and Water Supply Commission 
of Victoria, Australia, and has been extensively installed in Victoria, 
where 5000 are now in use. It has also been used quite extensively in 
New South Wales. 

The Dethridge meter consists of a wheel or drum to which pro- 
jecting pieces of sheet metal are fastened. The drum is placed with 
its axle horizontal and is set so that the projecting blades are in the 
current of the ditch to be measured. A special box is built around the 
wheel so that all water in passing has to strike against the blades. 
In this way the wheel turns in proportion to the amount of water 
passing. Knowing the number of revolutions of the wheel the amount 
of water passed can be determined. 

The illustrations given show one of these wheels set' in a concrete 
hex. but wooden boxes of similar form can be used. The whole 
structure is set just below the turnout gate, which is shown in the 
drawing. The bottom of the box is curved to fit the shape of the 
wheel. About % inch of clearance is left between the box and the 
blades. In use the water comes against each blade and pushes it 
around until the next blade strikes the water. In this way the space 
between the blades is filled with water, which is carried through the 
meter. The meter shown seems to have a normal capacity of 4 cubic 
feet per second and can be crowded to carry 5 cubic feet per second. 
This higher quantity, however, causes splashing over the top of the 
box. The fall needed to turn the meter varies with the amount beins: 



Bulletin 247 



IRRIGATION MEASURING DEVICES 



157 



measured, from y 2 inch for 1 cubic foot per second to 2% inches for 4 
cubic feet per second. This small required fall makes the use of this 
meter practicable in ditches with low grade. A counter is attached 




Fig. 19. — Drawing of Dethridge meter 

to one end of the axle and this indicates the number of revolutions 
which the meter has made at any time. The difference in the reading 
of the counter at any two times gives the number of revolutions the 
meter has made between the times of reading. By multiplying this 
number of revolutions by the number of cubic feet passed per revolu- 
tion, the total quantity of water received can be determined. It is 
most convenient to transfer the water "received into terms of acre-feet. 
If it is desired, with the Dethridge meter, to know the rate at which 
water is being received at any time it is only necessary to time the 
meter for one or more complete revolutions and divide the quantity 
passed per revolution by the time for one revolution. Thus, if it takes 
30 seconds for the meter to make one complete turn and it is known 



158 



UNIVERSITY OF CALIFORNIA — EXPERIMENT STATION 



from its rating that it passes 30.5 cubic feet for each turn, the rate of 
flow is 30.5 divided by 30, or a little over one cubic foot per second. 

The walls of the box in which the Dethridge meter is set are 4 
inches thick when made of concrete. Care should be used in getting 
the bottom curved to the correct circle so that the leakage around the 
meter will be small. This meter is somewhat complicated in construc- 
tion and it is better for it to be placed by canal companies than by land 
owners. It will probably cost less in this way as the drums can be 







H i 

mm P 



Fig. 20. — Photograph of Dethridge meter 



bought in quantities. In Australia the concrete box is made in parts 
and seasoned in the material yard, the parts being then cemented 
together when placed in the field. When built of concrete as shown in 
figures 17 and 18, 22.8 cubic feet of concrete and 40 board feet of 
lumber are required. The drums are best made by some sheet metal 
works. A special counter should be used made of rust resistant metal 
as the ordinary counters have been found to rust out rapidly in use. 
Where installed in large numbers in Australia the cost has been about 
$40 per meter ; the cost of the meter installed at Davis was about $60. 
The tests of this device made at Davis showed the meter to be quite 
accurate under constant ditch conditions between rates of flow of 1 to 
3.5 cubic feet per second. For both larger and smaller discharges the 



Bulletin 247 IRRIGATION MEASURING DEVICES 159 

meter passes more water than it does between these limits. The amount 
of water going through the meter varies with the depth of drowning. 
A meter set high in the ditch will discharge less water per revolution 
than one set low. Checking up the ditch below a meter so that the 
depth is increased at the meter may increase the discharge by as much 
as 10 per cent in some cases. This is discussed in detail in the 
appendix. 

The Dethridge meter of this size is adapted for accurate measure- 
ment of streams varying from "1 to 3 or 4 cubic feet per second ; in 
Australia it is considered satisfactory up to 5 cubic feet per second. 
Where the quantities are either larger or smaller than these amounts 
the error will be in favor of the water user. While rather expensive to 
install there are no parts which will wear out except possibly the 
counter. The bearings are merely oiled wooden blocks. Variations 
in the friction will not alter the discharge ; if the bearings are tight 
a greater fall will be needed to drive the wheel, but unless tighter than 
they will become if not tampered with, the discharge per revolution 
will not change. Where larger amounts are to be turned out, larger 
meters can be built or more than one installed. The meter has the 
advantage of being easily understood. The wheel stands up in the 
air and has a clumsy appearance, yet it is some advantage to be able to 
look across the field to the turnout and see by the turning of the wheel 
that water is still coming. When users realize that every turn of the 
wheel means so much water charged to them they will be more liable to 
economize in its use. 



Bill of Material for Dethridge Meter 

In addition to the 22.8 cubic feet of concrete required for this 
meter and the galvanized iron wheel, the following lumber is necessary : 

Bill of Material for Dethridge Meter 

Board feet 

1 pc. 3" X 4" X 4'-6" 4 

2 pc. 3" X 8" X 4' 16 

1 pc. 2" X 4" X 4'-6" 3 

4 pc. 2" X 1%" X 3' 3 

4 pc. 2" X 4" X 1' 3 

1 pc. 2" X 8" X4'-6" 3 

1 pc. 1^4" X 6" X 4' 3 

1 pc. 114" X 6" X 5' 3 

1 pc. 114" X 6" X 2'-4" 2 

Total 40 



160 



UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 



GEANT-MICHELL METER 



This meter is shown in figures 21 and 22. It consists of a wheel 
turning in a horizontal circular opening through w T hich the water is 
made to pass. This opening sets a little below the bottom of the ditch. 
The water in entering drops into a box set below the ditch bottom. 




SECT. ELEV. 



Fig. 21. — Plan and elevation of installation of Grant-Michel! meter 



passes under a cross wall, rises through the circular opening in which 
the meter is set, and passes on down the ditch. The meter consists of 
four flat blades set so that the water in flowing through the circular 
opening strikes against them at an angle. In this way the wheel is 
turned similarly to a wind mill. On the upper end of the shaft carry- 
ing the wheel is a counter which records the number of revolutions 
of the wheel. 

This meter is made in 4 sizes, 12-inch, 18-inch, 21-inch, and 39- 
inch. The size to be used is determined by the size of the circular 
opening. The rated capacities for these sizes given by the makers are 
1.66, 3.75, 5.83 and 16.66 cubic feet per second, respectively. The 



Bulletin 247 



IRRIGATION MEASURING DEVICES 



161 



wheel, counter, and standard for holding the wheel are sold and con- 
trolled by the patentees or their licensed agents. The prices quoted for 
Pacific Coast delivery, in lots of not less than 6, with freight but not 
duty paid, are $52.25, $66.75, $74.20 and $170.30, respectively, for 
the four sizes. The meter was invented by the two Australian engi- 
neers for whom it is named and 
has been used to some extent in that 
country, but it has been but little 
used in the United States. The box 
for the meter can be built of either 
wood or concrete; that installed at 
Davis is of wood. The standard 
for holding the meter is arranged 
so that the meter can be removed 
when not in use. On systems where 
the flow through each meter is not 
continuous, the meter can be used 
on more than one ditch, being 
moved around as water is turned 
out. 

The tests made at Davis of a 21- 
inch Grant-Michell meter showed 
that for discharges of over 2 cubic 

feet per second and up to 6.5 cubic feet per second, the meter makes 
one revolution for every 6.1 cubic feet of water passed. More water 
is passed per revolution on lower rates of discharge. The 24 tests 
made show that the meter will probably register within 2.5 per cent 
of the true quantity. The fall required in the ditch to get the water 
through the meter varies with the rate of flow. It is about 1 inch when 
the discharge is 3 cubic feet per second and rises to 4 inches with a 
flow of 5 cubic feet per second. 

This meter is not as much affected by changing the depths of water 
on the lower side as some others. The tests at Davis were made with 
varying depths but showed no regular differences. This is an ad- 
vantage when used on a ditch which is sometimes checked up. Its 
high cost, however, is against its general use. 




Fig. 22. — Photograph of installation 
of Grant-Michell meter 



HILL METER 

This device is shown in figures 23 and 24. It consists of a circular 

opening set horizontally in the floor of a box through which the water 

to be measured is made to pass. The meter consists of curved vanes set 

on a central drum. It sets in the center of the opening and is turn-d 



162 



UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 



by the water as it strikes against the vanes on rising through the open- 
ing. The turning of the meter drives the gears of a counting device 




SKETCH OF BOX U5ED IN TE5T5 OF 
12" HILL ME TER 



3-IO — 

Sect. Elev 



Fig. 23. — Sectional elevation of installation of 12-inch Hill meter 



which records the water passed in acre-feet. Different sized openings 
and meters are used for different sized quantities of water. The box 
in which the meter is set resembles a siphon. 

The Hill meter is patented and must be bought of the patentee or 
his licensed agents. While it has not been used to any extent as yet, 
and has not been pushed commercially, it is estimated that the meter 
alone, when manufactured in quantities, should cost about $10 each 
for the 12-inch size and about from $12 to $15 for the larger size, with 

a probable reduction with very 
large quantities. The cost of the 
structure for holding the 12-inch 
meter will vary from $10 to $15. 
It is stated by those who have de- 
veloped this meter that any kind 
of orifice in which the meter can 
be inserted so that its axis is verti- 
cal will do very nicely after the 
meter has been calibrated to suit 
that type of orifice. 

From a test of a 12-inch Hill 

meter at Davis it appears that this 

size of the meter will register the quantity passed within 1.5 per cent 

for discharges of from 1 to 3.5 cubic feet per second. For discharges 




Fig. 24. — Photograph of installation 
of 12-inch Hill meter 



Bulletin 247 



IRRIGATION MEASURING DEVICES 



163 



of less than 1 cubic foot per second, more water passes the meter than 
is registered. For discharges of 3.5 cubic feet per second the water 
boiled up through the opening so as to submerge the counter of the 
meter tested. By increasing the length of shaft of the meter higher 
discharges than this can be crowded through the 12-inch meter, but 
the greater loss of head required makes the use of larger meters 
preferable. 

The loss of head or fall in the water required for this meter varied 
from 1 inch, when carrying 1 cubic foot per second, to 6y 2 inches, 
when carrying 3.5 cubic feet per second. 

The Hill meter seems adapted to use under the usual conditions of 
irrigation practice. It is simple and has few wearing parts. The 
head required for the different sizes is less than that needed for the 
use of weirs. The record of the total quantity of water passed can be 
read in units of .001 acre-foot. 



HANNA METER 

As before stated, a Hanna meter has not yet been tested in the 
Davis laboratory. This meter has been designed by Mr. F. W. Hanna, 
supervising engineer of the U. S. 
Reclamation Service. The present 
retail price is $50. Figure 25 is 
taken from a photograph of one of 
these meters; figure 13 shows one 
installed with a Cipolletti weir. 

The Hanna meter differs from 
the Dethridge, Grant-Michell, and 
Hill meters previously described in 
being a device that registers the 
quantity passing through some 
other device rather than itself mak- 
ing the measurement. It differs 
from an ordinary water register in 
that it registers the quantity of 
water passing rather than merely 
the height of the water in some de- 
vice. It can be installed in connec- 
tion with a weir, a rating flume, an 
open channel, or a submerged ori- 
fice, or an orifice with free dis- 
charge, and will indicate on a counter, directly in acre-feet, the 
quantity of water passing. The mechanism of the meter is inclosed 



. , . 



Fig. 25. — Photograph of Hanna meter 



164 



UNIVERSITY OJ CALIFORNIA — EXPERIMENT STATION 



in a dust-proof metal box, shown in figure 13, and when installed this 
metal box rests on the top of a stilling box, also shown in the illus- 
tration, which communicates through a pipe with the stream being 
measured. A float resting on the water of the stilling box and an 
8-day clock together operate the meter. 



WATER REGISTERS 

Reference is made in the preceding pages to water registers for 
recording the height of water flowing over a weir or in a ditch or flume. 

In the main a water regis- 
ter (fig. 26) is composed of 
a cylinder on which a rec- 
ord sheet is fastened, a float 
which causes this cylinder 
to rotate as the water being 
registered raises and low- 
ers, and an eight-day clock 
which causes a pencil to 
travel horizontally the 
length of the cylinder each 
week, marking on the rec- 
ord sheet the height of the 
water as it travels. Water 
registers are usually set at 
the side of the ditch or weir 
carrying the water being 
measured, the float and 
counter- weight hanging in 
a stilling well, as shown for 
the Hanna meter (fig. 13) 
just described. The regis- 
ter sheets fastened on the 
cylinder are ruled horizon- 
tally to show feet and fractions of feet and vertically to show days 
and fractions of days. These sheets are changed once each week. To 
make use of the record they furnish it is necessary to use discharge 
tables giving the flow with different depths of water for the weir or 
flume in connection with which the register is set. As a rule water 
registers are not adapted to farm use. They require constant care 
and attention and, as indicated, considerable computation is necessary 
to determine from the register sheets and the discharge tables the 
quantity of water that has passed. 




Fig. 26. — Photograph of a water register 



Bulletin 247 



IRRIGATION MEASURING DEVICES 



165 



CURRENT METERS 

The standard instrument used for measuring the velocity of water 
in ditches and other open channels is the current meter. One of 
these instruments, with its 
full equipment, is shown in 
figure 27. Current meters 
are not used by farmers 
but one should be a part 
of the equipment of every 
canal superintendent or ir- 
rigation manager. They 
are mentioned here merely 
with the hope of encourag- 
ing their wider use by canal 
companies which have not 
been accustomed to use 
them and to make them 
generally familiar to farm- 
ers. Ordinarily it is not 
feasible to measure the 
water carried in main 
canals and main laterals by 
means of the devices that 
have been described in this 
Bulletin. Instead current- 
meter ratings are made at 
selected portions of the 
main canals and main lat- 
erals and from these tables 
are computed showing the 
quantity of water flowing 
at various depths. Stand- Fi< 
ard types of current meters 




-Photograph of current meter and 
equipment 



cost from about $75 to about $90, depending upon the style and equip- 
ment. As engineers and canal superintendents and irrigation managers 
are familiar with these instruments no description needs to be added. 



166 



UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 



APPENDIX 

DATA AND DISCUSSION OF TESTS OF MEASURING DEVICES AT DAVIS 

FIELD LABORATORY, JANUARY TO MARCH, 1914 



Area of 
opening in 
hydrant gate, 
square inches 
(equivalent 
to discharge, 
miner's inches) 

10 

10 
15 
25 
25 
15 = 25 
25 = 35 
25 = 35 
15 + 25 = 40 
15 + 25 = 40 



10 
10 

10 



Experiments and Discussion by S. T. Harding 



I. AZUSA HYDRANT. (Figures 3 and 4) 



Summary of Experiments 



Difference in 

discharge of 

orifices and 

weir, or error 

of measurement 

by orifices, 

per cent 


Area of 

opening in 

hydrant gate, 

square inches 

(equivalent to 

discharge, 
miner's inches) 




+ 6.31 




50 


—2.98 




50 


+3.65 


10 + 15 + 25 = 


:50 


+1.80 


10 + 50 = 


:60 


+5.80 


15 + 50 = 


:65 


+1.50 


25 + 50 = 


:75 


+1.50 


10 + 15 + 50 = 


:75 


+3.68 


10 + 25 + 50 = 


:85 


+ 1.70 


15 + 25 + 50 = 


:90 


+0.37 







Difference in 

discharge of 

orifices and 

weir, or error 

of measurement 

by orifices, 

per cent 

+0.85 

+ 2.00 

+ 1.00 

—1.38 

—0.39 

—2.20 

—1.30 

—0.84 

—2.14 



Mean 2.18 



Probable error of a single measurement +1.0. 



II. GAGE HYDRANT. (Figures 5 and 6) 

This hydrant consists of a 10-inch rectangular weir set in an open- 
ing in a vertical concrete box. The weir crest consists of pieces of iron 
strap i/g-inch thick set in mortar in the middle of the thickness of 
the box. It may be classed as having full contractions, although the 
nearness to the sides of the opening and to the sides of the box prob- 
ably affects the contraction. The detail of the crest is shown in the 
drawing. 

The experiments with this device consisted of 16 measurements 
with quantities varying from 0.15 to 1.13 cubic feet per second. The 
results of these are platted on the accompanying diagram. A hook 
gage was set in the back corner of the box with its zero point level 



Bulletin 247 



IRRIGATION MEASURING DEVICES 



167 



with the crest of the weir. A can 3 inches in diameter was used as 
a stilling box for this gage. Although the holes in this can were small, 
difficulty was experienced in getting accurate readings of the head 
due to the apparent " breathing' ' of the water, particularly at the 
higher heads. It is considered that this is the principal cause for 
the variation of the results of the separate measurements from the 
curve as shown on the diagram. Cross currents were very noticeable 
in the water in the box at the higher heads. Small shavings dropped 



6 

*, 5 

C 

°c 

D 












































/ 
























































\i 


/ 


/ 












s 


* 








































o 


^ / 


' 








f 


\£ 


t^ 












































/ 


' 








i ; 


3k 












































-P 


$ 








n ( 


\t 












































£ 


y 






fr 


fi 


< 














































A 








il° 




f 














































5°' 






v c 


$> 


s 


r 












































$ 


' 




$ 


r 














































,' 


^ 




K 


P 


* 














































, * 


*/ 


rf 


^ 


s> 
















































A 


is 


^ 


> 


















































< 


z 


4 


s 






















































op 


* 




















































■ o 


>/ 


0>| 






















































V 
























































t 
























































/ 
$ 
























































tb 


7a 






















































fi 


% 
























































& 


/ 

























































V 
























































J 


/ 
























































t 


























































f 




















































) /O 20 30 40 50 
ischarge in Miners Inches— 50 Miners Inches^ 1 Second Foot 





Eating Curve for Gage Hydrant 

into certain parts of the surface of the water would be sucked several 
inches below the crest of the weir before passing over it. Under such 
conditions it is not to be expected that the standard weir formula 
would apply. For purposes of comparison the discharge of a 10-inch 
weir computed from the formula Q = 3.33 (1— .2h) h% is plotted on 
the diagram. This shows the device to give increasingly greater dis- 
charges than a similar standard weir as the head increases. 

The half-round section of 18-inch pipe used as an outlet for the 
water after it passes the weir was of sufficient size to discharge the 



168 UNIVERSITY OP CALIFORNIA EXPERIMENT STATION 

water received without submerging the w T eir. However, at the higher 
heads used the water below the weir was but little below the crest 
of the weir. The accuracy of measurements w T ith this device unc^er 
field conditions will depend to a considerable extent on the accuracy 
with which the reading of the head of the crest can be made. The 
usual method is to set a bracket at the back side of the box with its top 
level Avith the discharge crest. By setting a rule on this bracket the 
depth can be read directly. With the hook gage and stilling box used 
in these experiments the average variation of the 16 measurements 
from the curve was 3.5 per cent. With measurements of the head in 
open water the error to be expected would be much greater. 

Some measurements were also made on this hydrant before the 
sharp edge was set, using the 2-inch concrete wall as a discharge crest. 
The heads were read on a staff gage, the water being stilled in front 
of this w T ith a piece of wood at the times of the readings. A total of 
7 measurements were made, with discharges varying from 0.18 to 0.96 
cubic foot per second. The crest was 13% inches long. A comparison 
of the rating curve obtained from these measurements with a com- 
puted curve for a sharp crested weir of the same length showed that 
on the lower heads, where the thickness of the concrete is sufficient to 
give broad crested weir conditions, the discharge is less than for a 
sharp crested weir, and that on the higher heads, where the lower 
contraction is complete, the measured curve gives higher discharges 
than the sharp crested weir, being similar to the results on the same 
box after a sharp edge was installed. 



Summary of Experiments 

Head Actual SSSSS? Differ " Head Actual SSBSJ? Differ - 

on discharge, n-fofn %i ence - on discharge, n _« ,0/1 o'u ence, 

weir, cu.ft. Q ^cuff per T 6ir ' CU - ft - %/luft P er 

feet per. sec. ^Te'c ce ^ feet P er sec - per see cent 

0.128 0.152 0.121 26 0.355 0.627 0.537 16 

.166 .202 .180 12 .392 .804 .617 30 

.211 .288 .253 14 .393 .829 .618 34 

.213 .284 .258 10 .401 .864 .633 36 

.260 .413 .343 20 .435 .958 .709 35 

.298 .506 .418 21 .446 .978 .735 33 

.313 .548 .442 24 .471 1.000 .795 26 

.342 .652 .509 28 .494 1.134 .846 34 



Bulletin 247 



IRRIGATION MEASURING DEVICES 



169 



III. KIVERSIDE BOX (Figures 7 and 8) 
Summary of Experiments 



Area of 

opening in 

gate, sq. in. 

(equivalent to 

discharge in 

miner's inches) 

10. 

10. 

14.6 

15. 

15. 

20. 

25. 

25. 

27.5 

32.5 

33. 

35. 



Difference in 

discharge of 

orifice and weir, 

or error in 
measurement by 
orifice, per cent 


Area of 

opening in 

gate, sq. in. 

(equivalent to 

discharge in 

miner's inches) 


+ 4.10 


40. 


—3.38 


40. 


+ 4.45 


43. 


+ 1.86 


44.5 


+ 1.46 


48. 


—3.54 


50. 


—1.11 


50. 


+4.70 


57.5 


—1.53 


58. 


+3.03 


65. 


+0.15 


75. 


+ 1.00 


75. 



Difference in 

discharge of 

orifice and weir, 

or error in 
measurement by 
orifice, per cent 

—1.9 

+ 0.40 

+3.16 

+ 2.3 

+ .41 

+1.59 

+ 4.05 

+1.25 

— .16 

— .26 
—1.63 
—1.08 



Mean +1.95 



IV. FOOTE INCH BOX (Figures 9 and 10) 



Summary of Experiments 



Length of 
opening in 
box, inches 


Discharge 

measured by 

box = length 

times height 

(4), =r miner's 

inches 


Discharge 
measured by 

weir, 
miner's inches 


Difference 

in discharge, 

or error 

of measurement 

by box, 

per cent 


4 11 /l6 


18.75 


19.50 


—4.00 


6%6 


25.25 


24.95 


+ 1.19 


8%6 


32.75 


32.25 


+ 1.53 


9 5 /l6 


37.25 


36.50 


+ 2.01 


11% 


46.00 


44.70 


+2.83 


151/4 


61.00 


60.20 


+1.31 


16% 


66.75 


62.95 


+5.69 


19y 4 


77.00 


72.45 


+5.91 


20 


80.00 


78.85 


+ 1.44 


21 % 


85.00 


79.40 


+ 6.59 


22y 2 


90.00 


86.50 


+ 3.89 


25% 


102.50 


95.40 


+ 6.92 


27% 


110.75 


101.95 


+ 7.93 


29% 


117.50 


108.90 


+7.32 


31% 


125.00 


118.75 


+ 5.00 


32i/ 16 


128.25 


124.50 


+2.92 


37H 6 


148.25 


147.40 
Mean 


+ 0.58 




+3.95 



170 UNIVERSITY OF CALIFORNIA — EXPERIMENT STATION 

V. SJBMERGED ORIFICE HEADGATES. (Figures 17 and 18) 

The accompanying table shows the results of the tests made at 
Davis in January, 1914 of a gate 36% 6 inches wide of the type used 
by the Kern County Land Company. The discharges were measured 
over a 3-foot Cipolletti weir and checked volumetrically from the 
reservoir. 

The loss of head was measured in four different ways, viz : by hook 
gages about 6 feet above and below the gate, by staff gages at the 
same points, by measurements down from a level board about 1 foot 
above and below the gate, and by measurement down from the top 
of the gate on the upper and lower sides. Stilling boxes were used 
with the hook gages. At higher rates of discharge the depth of sub- 
mergence was not sufficient to cause the water on the lower side to 
back up on the gate, so that the measurement on the lower side of 
the gate was of no value. 

In several of the runs the discharges were small in proportion to 
the capacity of the gate, and the loss of head too small to be accurately 
measured. Two means are given, one being for all tests, the other 
including only those runs having a height of opening of 1 inch or 
over, a loss of head of over 0.05 foot, and a depth of submergence of 
0.10 foot or over. This latter mean is the better one. It should be 
remembered in interpreting these tests that the maximum discharge 
used is much less than the capacity of the gate and that the values 
of the coefficient for higher rates of discharge might be different, 
probably less than those given. 

The average variation of each observation from the mean was 
about 4 to 5 per cent, for the different methods of measuring the loss 
of head. The greater variation of results of the measurements on the 
gate shows in these tests. This method should not be used. 

Tests were also made of a gate 31% inches wide set across the 
3-foot concrete testing flume of the field laboratory. Side guides 2 
inches by 4 inches and a sill 2 inches by 6 inches, were set in the flume. 
The loss of head was measured in the same four ways as in the case 
of the tests of the other gate. The results of these tests are also 
shown in a table. The coefficients for the measurements with hook 
and staff gages are higher than those found when measuring with the 
level board or for the other gate tested. 

The results of these tests and other available data indicate that, 
while such a submerged orifice headgate is not a desirable type of 
measuring device, under certain conditions of necessity it can be used 
with fairly satisfactory results. On any system a standard type and 



Summary of Experiments on Submerged Orifice Headgate 

Loss of head by. feet 



of Type Used by Kern County Land Co. Gate 36% 6 Inches Wide. Tests Made at Davis, Calif., January, 1914 



ber charges, 



4 .503 

5 .511 

6 .793 

7 .806 

8 .816 

9 1.46 

10 1.43 

11 1.43 

12 1.40 

13 .813 

14 .826 

15 .811 
16 



inches sq. feet 



3.01 
2.66 
2.72 

2.38 



2.01 

2.01 



% 
% 
2% 
1%6 



%6 

3% 

1% 

2% 
3% 

2 

1% 

1% 



4% 
1% 



0.158 
0.191 
0.637 

0.400 
0.287 

0.143 
0.985 
0.381 
0.635 



0.445 
0.756 
0.573 
1.017 
1.275 
0.891 
1.144 
1.32 
0.629 
0.445 



.021 
.046 
.073 
.173 
.511 
.022 
.355 
.137 

.049 
.033 



.15 .13 .135 

.025 .02 .02 

.05 .05 .045 

07 .075 

.17 .17 .195 

.51 .54 .55 

.035 .02 .01 



.85 
.265 

.420 
.18 
.28 
.39 
.12 
.17 



.35 .42 
.135 .16 



.115 .135 

.92 1.08 

.36 .47 
.61 

.125 .205 

.09 .13 

.135 .19 

.065 .095 



.45 



25 1 

26 3.34 5 1.275 .152 

27 3.31 4 1.02 .271 

28 3.34 3 0.762 .385 

29 3.31 6 1.525 .088 

30 4.20 6 1.525 .166 .17 .155 

31 4.26 5 1.275 .255 .28 .28 

32 4.24 4 1.02 .457 .47 .51 
Number of observations 

Mean coefficient for all experiments 
Rejecting experiments with height r 

of opening less than 1 inch, loss No. of observatior 
of head less than 0.05 foot, ami J Mean coefficients 
depth of submergence less than Per cent variation 
0.10 foot. I 



Coefficient in formula 
Q = ACVjfch Erom - 



' coefficient from, 



.739 
.688 
.576 
.765 
.744 
.908 
.764 



.700 
.740 



.781 

955 .943 

83 1.035 

04 .735 

62 .705 

19 .709 

26 .702 

44 .666 

29 .718 

82 .724 

79 .815 

31 .640 



.646 
.744 
.653 
.709 



+.140 
+.133 
—.129 



+.016 

—.010 
—.054 
—.070 
—.066 
—.071 
—.058 
—.044 



-.036 
-.005 
-.055 



—.016 

+.023 
—.042 



+.082 
+ .101 
+ .032 
+ .016 
—.040 
30 



Staff 

+.176 
+ .070 
—.147 
—.088 



.057 



+.015 

+ .043 
+.078 



—.001 
+.116 
+.011 
+ .063 
+ .019 
+ .001 



+ .095 
—.116 
—.116 
+.025 
+ .021 
+.139 
—.033 
—.012 
—.054 
+ .003 
+.010 

+.013 



—.085 
—.059 
+.009 
+ .076 
—.041 
+.038 
—.039 
—.081 
—.046 
+ .012 
—.021 
—.024 
+ .038 
+ .055 
—.028 
—.087 
32 
.055 



gate 
+ .146 
+ .138 
—.055 
—.015 
+ .055 



—.020 
—.050 
—.046 
—.053 



—.046 
—.012 
—.065 
—.039 



-.040 
-.056 



.028 —.043 

+.013 

.042 —.014 

-.016 —.016 

.096 +.101 

.046 +.048 

.030 +.004 

-.026 —.014 
19 20 

.035 .038 



.092 
-.063 



+.006 
+.093 



+ .025 


—.072 


—.025 


—.063 


+.054 


—.009 


—.065 


—.028 


—.030 


—.002 


+.028 




—.005 




—.008 




+ .071 




—.012 




—.071 





Bulletin 24' 



IRRIGATION MEASURING DEVICES 



171 



soui^wtoi-'OCooMaai^wKi 



§•1 

O <T> 

O ^ 



Ol OS 
OS M 

Ol OS 



O H OS b CO °-l M 00 M Ol 00 _ 



b *-<j 



©<l(OHO(»tOOt»'' 
tOtOOlCfltOOSCDgSI 



wa^MWrfs-wastoMi^oiffitoKiw^oitoco^ 



- o S'^ o 2. 

Ol B'ora 2 '-"en? 



CO CO 
CO CO 
rf^ CO 





OS 

CO 


00 

CO 


M 
o 


CO 

to 






OS 
OS 


00 
00 


o 


4- 


OS 

OS 


00 

oo 


i— 1 w,a<? 


b 

c 


-1 


CO 

os 


to 
to 


os 

CO 


co 
-1 

o 


-i 

co 


W 
Ol 
OS 




M 

co 

IC 


CO 

to 

00 


~1 
o 


b 

CO 
M 


1— ' co fv 



co -i rf^ to to co f-» M Or? 

M <l H 'Jl O W N O Q » 3j 



M-l^bOtOWMMO 

ascoasoocooioooo 



corf^oooicococoro 



00 


00 


oc 


to 


OS 


-) 


CO 


o 


00 


to 


CO 


to 



oo oo 
oo Ol 
-i oo 



ore M 

(xitDOocctocooooooococoootofflffW 

OlOOOOSCOOCOCS^I— ' O CO CO Ol d? 2. 



O Ol A Ol H v) 



O W S W H 



oo oo oo 
co co i— 1 
rf^ — i as 



00 oo co 

01 Ol H 
#» I— ' Ol 



00 ~q 

rf^ CO 
00 (-> 



oo oo oo oo oo oo 
co os co oo -q o 
as cs o o 00 -3 



OO 00 00 S <1 00 M O 53 « 
COOM-^COCOCOOOOsarqff 



co oo -i 

O (-> oo 



CO oo -1 
CO Ol CO 
Ol (- 1 CO 



OO •<! 

O M 



^i os -i oo -i -i -q oo 

— 1 OS —1 i— > co «o rf^ 1— ' 
oicooocooscococo 



oo s <i s s s oo oo 

to oi co os ~~i os --I co p 

M-dOl— 'OlOOOOl^ 

p. 



?r 



os os os 

CO CO 00 

13 M H 



a a <) s ^i <i s <i s <i <i S O 

^tOOlOOtOMOOO^^MS.3 
-.lCOt->rfxrfxOlOOSOOSCoa> . 



II g, 

>2. 
£3 



O 4 

BB 



^COC0COCOC0C0C0OlCOCOCOC0C0^00Ol^^Ot4^COC0a£R o xt 

ww^cc5Ki^oioi(»oiw<iwoieiJwoiwHocooij(j(Dg; 



+ + + 

b b b 

O CO ^ 

^ Ol H 



I + + 



o o o 

WHO 

-q os co 



+ J J J J J J J + +*w 

b b b b ore 2 

os rf^ oi co 2 £- 
oo s to h" 5 ^ 



o o o o o o 

OS OS tf^ CO CO Ol 

co i— ' -q oo oi h-» 



I + + + + 



I + I I + I I I + I I I + + 



- 


o o o 


o o o o o o o 


© 


CO 


O t— CO 


M S M ^ Ol CC O 


CO 


CO 


-5 00 o 


•<! 1— » O CO CO CO QO 


10 



©OOOOOOOOOOI- i arap 

OHWMOWOWWM*.W^ 



I+ + + +I | |+ + + +|H- 



CO 

bobooooooo 

coot— 'coosocoh- ' 

©COCOOll-'COOCO 



I I i 



h-» o 
H DO M 

01 s to 



o o o 
CO o o 

CO OS CO 



o o o o 

►Ji. CO CO CO 

l—i CO I— ' CO 



o 

CO 
O CO Ol 



o o o o g • 

' CO CO rf^ 3 < 
© 00 Ol ^ 



I I 



I I 



o o o 

CO CO CO 
CO CO CO 



+ + + + J + + + J «o 

© © © © b b b © © © © £- &■ 

aCC05v)HOH^bOWO» 

-aoi^-ioot-'rfi.coascoi-' 



^ OS CO 



W W W a Ol CO W CO W |fk It. W M CO to M M ^ (fjg - 

_ a w '^ b b rf^ b to If^ h w bo a s to b ™ * S 5 s n 

Ol OS OS CO CO 00 



os^-orf^rf^cooscotf^ocohf^bsi. 

OffiOOSlf'OltOOlOlQOtO^ p p 'g. «• 



172 UNIVERSITY OF CALIFORNIA — EXPERIMENT STATION 

size of gate should be adopted and strictly adhered to. This should 
then be rated for the conditions of use, using the same method of read- 
ing the loss of head that will be used in practice. The coefficient 
derived from the rating should then be used for the type of gate 
rated. In use, care should be taken to maintain the conditions under 
which the rating was made and prevent silting of the channel above 
or other changes. 



VI. DETHRIDGE METER. (Figures 19 and 20) 

This device was tested by running water through it which had 
been measured over a weir and also volumetrically measured from the 
reservoir. The rate of flow was kept practically constant. The time 
of run. number of revolutions, and rate of flow gave data on which 
the number of cubic feet passed per revolution could be computed. 
Gages were set above and below the meter from which the loss of 
head could be obtained. 

The installation of the meter is shown in the drawing. Immedi- 
ately at the lower end of the concrete there was a drop into the waste 
channel. When first tested the water passed through the meter over 
18 inches of floor, and then had a free fall to the waste channel. The 
measurements in this first test were representative of one extreme of 
conditions under which the meter might be installed. The rating curve 
derived from them is marked No. 1. Later a section of flume 3 feet 
wide and 12 feet long was built out from the concrete. This was 
similar to the usual ditch conditions, the water having a greater depth 
over the lower sill of the meter than in the first run. The rating curve 
derived from these tests is marked No. 2. The rating curve furnished 
by the State Rivers and Water Supply Commission of Victoria is 
shown by dotted line adjacent to curves Nos. 1 and 2. 

In addition to the tests mentioned above, checks were placed in 
the flume and four single tests were made with different depths of 
submergence. The figures obtained are shown in the table of results 
and are plotted above rating curve No. 2. 

Rating curve No. 1 agrees very closely with that used in Victoria. 
It is the practice there to set the floor of the meter box rather high 
in the laterals. The full supply level shown on their drawings is 
about 10 inches below the axle of the meter. By setting the meter 
high in the ditch, more constant conditions are secured, as checking 
of the lateral below can not submerge the meter to as great an extent. 
However, this requires an additional fall below the meter which is 
not always available. The conditions obtained in the second run are 



_ 



Erratum: "Grant-Michell Meter," in title to curves on page 173, should 
read "Dethridge Meter." 



Bulletin 247 



IRRIGATION MEASURING DEVICES 



173 



4.0 
v. 

| 
I so 

1 
s 

u 

.u 

^§ 

^0.0 
t 
































































\ 






















































\ 










































































•• 


/? 


7/ 




ri 


C6 


/r 


/^ 


n 


0- 


2 
















• 












*M- 




i—H 


1 


r 




h4 


9 




























-< 


^ 




























-J 


"M 
































Rt 


it/ 


nc 


? 


S^ 


r* 


e 


n< 


2 


/ 








































~* 








































































































































































































■ 6/4 
































































































X 
















-4-; 








































■&- 














*-- 


' qj 






































V 


i * 










^^ ^ 5 ^ 






































g, * 


71 










^' 




uj "- 




































,W 


v 


















q 


































. 


«" 


/ 








^ 












































I> 


/* 








•^ 












































id 


> 








< 


;/ 












- n? ^ 




























r 1 


^e ( 


\' 








-^ 


W 














c/Z \5 




























f 1 






*» 




""' 




1 '' 














«ij 
































~* 


j 


^ 


f\ 


















--C: 






















i ( 


S 3 


5^ 








i 


r L 




















v. 






















V 


ass 










/.J 






















- n i ° 
















• 












"•"'' 


W 


S> ^ 






































^=5 




< 


L«- 




i*> 


rff 


i ' 


























10 








•s- 














1 


r^ J 


































0/234 5 
Discharge in second feel 



Rating Curves for Grant Michell Meter 
Note. — Dotted curves furnished by State Rivers and Water Supply Commission of 

Victoria, Australia 



typical of unchecked ditches. The depth of water below and also of 
submergence of the meter vary with the quantity flowing similarly to 
the variation in depth in a ditch not controlled by checks. 

Each curve is consistent within itself. In curve No. 1 the average 
variation from the curve of the 7 points used to locate the curve is 
only 0.1 of a cubic foot per revolution, or about % of 1 per cent. In 
curve No. 2 the average variation from the curve of the 12 points 
used to locate the curve is 0.15 of a cubic foot per revolution, or V 2 
of 1 per cent. 

With a meter of this type, which records in total quantities passed 
without showing the rate of flow, the ideal rating curve is a straight 
line which should be horizontal on the diagram. The discharge per 
revolution would then be independent of the rate of flow. It is not 
to be expected that this result can be obtained at either extreme of 
the capacity of any meter. With smaller discharges the leakage would 
be expected to be greater due to the slower movement of the wheel. 
Also, at higher discharges the greater depth of flow through the meter 
increases the leakage area. Both curves show this feature of increas- 
ing discharge per revolution at either low or high discharges. The 
range of capacity for this size wheel is considered to be from 1 to 4 



174 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 

cubic feet per second. A uniform rating is used between these dis- 
charges. The mean quantities discharged per revolution of the meter 
for all tests between 1 and 4 cubic feet per second were 28.75 cubic 
feet on curve No. 1 and 30.4 cubic feet on curve No. 2. The mean 
variation of the six tests on curve No. 1 from this average was 1 pei 
cent and on curve No. 2, % of 1 per cent. Under conditions such as 
existed in either of these runs the use of 15.2 and 14.3 revolutions per 
0.01 acre-foot should give close results on curves Nos. 1 and 2. re- 
spectively. 

Four additional tests were made with discharges of a little over 2 
cubic feet per second, the depth of submergence being varied by 
checks in the flume. With depths of water of 0.45, 0.77, 1.01, and 1.20 
feet on the lower sill of the meter, the quantities discharged per revo- 
lution of the meter were 30.5, 31.5, 32.5, and 33.0 cubic feet, re- 
spectively. 

The height of the blades is 10 inches, the diameter of the drum is 
3 feet 4 inches, and the length of the drum is 2 feet 6 inches. The 
volume contained between the drum and outer edge of the blades is 
27.3 cubic feet. If there were no leakage the meter would pass this 
amount per revolution. The clearance is from 14 to % of one inch. 
Under the conditions of small depth of water indicated in curve No. 1, 
the quantity passed was 28.75 cubic feet per revolution. Under con- 
ditions represented by curve No. 2, where the depth was greater, it 
was 30.4 cubic feet, and on the single test of maximum depth it was 
33.0 cubic feet. These indicate slippages of 5.3, 11.4, and 20 per cent, 
respectively. 

From these tests it would appear that a rating can be determined 
quite closely for any fixed condition under which the meter may 
operate. The accuracy obtained when using such a rating under such 
conditions of free fall or of unchecked ditch should be sufficient for 
any usual needs. When placed in ditches where variable submergence 
may be caused by checking up below, the rating will be subject to 
variations which may be as much as 10 to 15 per cent. The same effect 
might occur when installed in an unchecked ditch as shown in curve 
No. 2, due to natural checking during the season from weed growth 
in the ditch. 

It would seem advisable where possible to install this meter as 
high in the ditch as conditions will permit, as under such settings the 
rating will be less liable to variation. 

Where this is not practicable the rating should be chosen for the 
depth of submergence and the conditions in the ditch below kept as 
constant as possible. 



Bulletin 247 



IRRIGATION MEASURING DEVICES 



175 



The loss of head curves are also shown in the diagram. For the 
range of capacity of the meter the loss of head is quite small. The 
curve represents the head required to turn the meter; any raising of 
the meter in the ditch to prevent submergence would require addi- 
tional fall. The three curves are plotted similarly to those for the 
rating of the meter. Less head seems to be required for the sub- 
merged condition. 



Summary of Experiments 



Rate of 

discharge, 

cu. ft. 

per sec. 


Total 

number of 

cubic feet 

passing the 

meter 


Number 

of 

revolutions 

of meter 


Cubic feet 

passing 

the meter 

per 
revolution 


Loss 
of head 
through 

meter, 
feet 


Depth 

of 

water in 

outlet, 

feet 




Eating under 


unchecked ditch 


conditions 


(Curve No. 2) 




0.25 


407 


11 


37.0 


.015 


0.14 


.66 


708 


22 


32.4 


.02 


.19 


.96 


1906 


62 


30.7 


.05 


.40 


1.28 


908 


30 


30.3 


.04 


.30 


1.68 


1454 


48 


30.6 


.05 


.36 


1.99 


726 


24 


30.3 


.07 


.35 


2.46 


874 


29 


30.2 


.08 


.46 


2.94 


1291 


43 


30.0 


.09 


.51 


3.38 


1900 


62 


30.6 


.15 


.56 


4.26 


1857 


59 


31.5 


.23 


.62 


5.29 


1732 


54 


32.0 


.31 


.88 



Eating for meter set high in ditch with excess fall below outlet sill of meter 

(Curve No. 1) 



.51 


911 


30 


30.4 


.04 


.12 


1.04 


1532 


53 


28.9 


.07 


.17 


1.45 


1688 


59 


28.6 


.09 


.20 


1.95 


2891 


102 


28.3 


.10 


.25 


2.05 


2113 


74 


28.55 


.09 


.28 


3.57 


1318 


45 


29.3 


.23 


.32 


4.05 


575 


20 


28.8 


.32 


.35 




Eating wi 


th variable 


depth of submergence 




2.16 


1069 


35 


30.5 


.15 


.45 


2.37 


945 


30 


31.5 


.11 


.77 


2.33 


942 


29 


32.5 


.13 


1.01 


2.25 


990 


30 


33.0 


.14 


1.20 



176 



UNIVERSITY OF CALIFORNIA — EXPERIMENT STATION 



VII. GRANT-MICHELL METER. (Figures 21 and 22) 
The tests of this meter are summarized in the accompanying table. 
Quantities varying from 0.5 to 6.5 cubic feet per second were run 
through the meter, the depth of water in the outlet being varied by 
checks. No regular variation of the discharge per revolution was ap- 
parent when discharging under varying submergence. The dial at- 
tached to this meter is graduated to read to 0.01 acre-inch. One- 
hundredth of an acre-inch equals 36.4 cubic feet. The meter was set 
up and several counts of the number of revolutions required to equal 
0.1 acre-inch on the dial made. These showed 68 revolutions for 0.1 
acre-inch, indicating that the dial is graduated to pass 5.35 cubic feet 
per revolution of the meter. The mean values found from the tests 
for discharges over 2 cubic feet per second was 6.10 cubic feet per 
revolution. For the size of meter used and the conditions of operation 
encountered, the gearing of the dial needs rearrangement. The box 
and setting were built according to the patentee's plans. 

A total of 30 single runs were used in plotting the rating curve. 
It was found that a horizontal straight line fitted the points having 
discharge over 2 cubic feet per second as well as any curve. The 
average variation of the 24 tests at discharges over 2 cubic feet per 
second was 2.3 per cent. The same quantities were run through the 
meter, with checks varying from to 12 inches high set in the outlet 
flume, without giving any apparent variation in the discharge per 
revolution. The quantities run with no checks gave somewhat more 
variable results, due apparently to the rougher water and more dis- 



e 

$ 6 



< 

V) 

*0 n 






































































































































































































































\ 












































































\. 










































































K 














































































^ 


















































































.•* 


l_ 








=i 


I 


i 








■ 


a 


, r 


-' 


c 


w 


"vt 










































, — a 


•^ 


i — i 


■ 


• 






* 




1 




* 




— •■ 




























■0.4^ 

- ^ 

- 02 .| 

-o.i « 

o 
^1 


















































































































































































































































































































































































































































































































/ 








































































/ 








































































/ 






































































( ( 


\ 


* 








































































/ 






































































V 


4 








































































/ 






































































•v- 


s 






































































h< 


/ 






































































S 






• 


































































■■> 


S 




































































1 




^ 




































































•- 


r* 


<* 






































































** 


1 








































































































































































































































































c 


l 2 3 A 5 6 7 
Discharge in second feet 





Rating Curve for Grant Michell Meter 



Bulletin 247 



IRRIGATION MEASURING DEVICES 



177 



turbed conditions. This constancy of discharge is probably due to 
the fact that the meter is set below the bottom of the outlet ditch, and 
is always submerged to a considerable depth. The rating curve rises 
at lower heads, as is to be expected. 

The loss of head curve was also plotted from the reading's of gages 
above and below the meter. The points obtained from tests where no 
checks were used were omitted on this curve as the loss of head in such 
cases would depend on the location of the gage. The outlet flume was 
not long enough for the water to become settled before reaching the 
spillway. 



Summary of Experiments 



Actual 

mean 

discharge, 

cu. feet 
per-second 


Number of 
1-100 acre- 
inches 
recorded 
on dial 


Total 

number of 

cubic feet 

passing 

meter 


Cubic feet 
passing meter 
per 1-100 
acre-inch 
recorded 


Cubic feet 

passing 

meter per 

revolution 

of meter 


Loss of 

head 
through 

meter, 
feet 


Depth of 

water in 

outlet 

ditch, 

feet 


.51 


14. 


694.7 


49.6 


7.30 


0.00 


0.84 


.71 


19. 


903.4 


47.5 


6.99 


.005 


1.06 


1.00 


20. 


901.3 


45.1 


6.64 


.02 


1.11 


1.29 


23. 


987.0 


42.8 


6.30 


.01 


1.19 


1.72 


27. 


1134. 


42.0 


6.18 


.15 


.53 


1.85 


16. 


688.0 


43.0 


6.33 


.13 


.66 


1.95 


16. 


685.9 


42.85 


6.30 


.30 


.38 


2.16 


13. 


532.4 


41.0 


6.03 


.04 


1.30 


2.24 


36. 


1468. 


40.8 


6.00 


.05 


1.30 


2.35 


14. 


571.8 


40.8 


6.00 


.06 


1.31 


2.57 


19. 


774.5 


40.8 


6.00 


.07 


1.34 


2.72 


22.5 


983. 


43.7 


6.45 


.10 


.87 


2.76 


16. 


665.6 


41.6 


6.12 


.07 


1.38 


2.88 


41. 


1681. 


41.0 


6.03 


.11 


1.38 


2.95 


28.3 


1239. 


43.7 


6.45 


.10 


1.06 


3.00 


51.3 


2165. 


42.2 


6.21 


.45 


.28 


3.18 


24. 


1032. 


43.0 


6.33 


.09 


1.26 


3.19 


43.4 


1913. 


44.0 


6.47 


.11 


1.38 


3.42 


38. 


1565. 


41.2 


6.06 


.23 


1.34 


3.43 


45. 


1786. 


39.7 


5.86 


.04 


1.34 


3.45 


21. 


884. 


42.1 


6.19 


.13 


1.42 


3.56 


30.4 


1276. 


42.0 


6.18 


.20 


.95 


3.95 


28.8 


1185. 


41.2 


6.06 


.46 


1.27 


4.00 


80.5 


3361. 


41.9 


6.16 


.18 


1.18 


4.27 


20. 


799.1 


40.0 


5.89 


.19 


1.53 


4.74 


105. 


4263. 


40.6 


5.9/ 


.28 


1.05 


5.06 


25. 


1031. 


41.25 


6.07 


.34 


1.61 


5.52 


58. 


2362. 


40.7 


5.99 


.23 


.98 


6.57 


66. 


2762. 


41.8 


6.15 







178 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 

These tests indicate that this meter can be rated with sufficient 
accuracy for the usual requirements of irrigation work. A correctly 
calibrated dial reading in acre-feet is an advantage, as any user can 
see for himself the amount of water he has received. The removable 
meter and head reduces the number of meters required, which at the 
quoted price of these meters is quite an item. This meter is similar in 
type to the Hill meter, which has curved vanes instead of flat ones. 



VIII. 12-INCH HILL METEE. (Figures 23 and 24) 

Tests were made of a 12-inch Hill meter. A 27-inch meter and 
box had previously been installed but the capacity of this size of meter 
was larger than the discharges available at the experimental plant. 
The opening for the 12-inch meter was set in the box previously built 
for the 27-inch meter. This probably affected the loss of head but 
should not affect the meter rating. 

The meter as supplied was geared to a Veeder counter with a gear 
ratio of 1 to 90. As the last figure on the counter is intended to rep- 
resent yiooo of an acre-foot, each revolution of the meter is equivalent 
to .484 cubic foot of water. 

Eleven tests were made with discharges varying from 0.21 to 3.34 
cubic feet per second. In addition, six tests were made with dis- 
charges varying from 1.18 to 1.56 cubic feet per second, and with 
varying depths of submergence. These are all summarized in the ac- 
companying table. 

For discharges of from 1 to 3.5 cubic feet per second, the rating 
curve is a horizontal straight line. The 7 points used to locate this 
line give an average number of cubic feet passed, per Vlooo acre-foot 
on the counter, of 43.4, or 0.3 per cent less than recorded. In these 
seven tests the depth of water in the outlet was varied as it would be 
in an unchecked ditch, the depth depending on the rate of discharge. 
Points for discharges of less than 1 cubic foot per second were not 
included in this average as the rating curve rises for these lower dis- 
charges, more water passing the meter than is recorded. 

The maximum capacity of this meter as set was 3.5 cubic feet per 
second. For this discharge the water rose to the counter when coming 
through the orifice. By using a longer shaft on the meter higher rates 
of discharge can be crowded through this meter but the use of a larger 
meter would be preferable. 

The additional tests made with variable depths of submergence 
did not give as uniform results, the six tests averaging 3.2 per cent 



Bulletin 247 



IRRIGATION MEASURING DEVICES 



179 



more discharge than recorded. The average of the thirteen tests made 
with discharges over 1 cubic foot per second gave 1.3 per cent more 
water passed by the meter than recorded. Data regarding tests of this 
same meter made by the U. S. Reclamation Service at Boise, Idaho, 
have been furnished for comparison. A total of twenty-three tests made 
by the Reclamation Service averaged 2.5 per cent more water passed 
than was recorded. The discharges in these tests varied from 1.11 to 
3.96 cubic feet per second. 

The loss of head curve for different rates of discharge is also 
shown. It should be remembered that the box used is larger than the 
standard for this size of meter. This reduces the total loss of head 
somewhat, although the main loss should be in passing through the 
12-inch opening. The loss of head reached a maximum of 0.5 foot for 
a discharge of 3.5 cubic feet per second. In the Boise experiments 
mentioned above the loss of head was 0.87 foot for the same discharge. 

From these tests it would seem that this meter will measure and 
record the quantity of water passing with sufficient accuracy for 
irrigation needs when the size of meter is chosen to fit the rates of 
flow to be received. The loss of head can be kept below that required 
for a weir by such selection of sizes. The opening in which the meter 
is set is 9 inches in height. This height is an advantage as the lines 



50 

1 

k>20 

l 

a 

8' 








































































.50 

**> 




\ 


V 








































































\ 














































































« 


# 
















































































•« 


i 




h 


a 


\i t 


"><i 


( 


A 


•r 


ye 




















































• 






-» 
























« 










































9 










































































































































































































































































































































































































































































































































































































































































r N 


fB 




























































i 


I 


^ 






























































H 


.i L 


S 


s 
























































c 


o 




s 


^ 1 
























































1 





J 






























































• 




























































i 


i> 


































































*""« 


























































• * 






















































y . / . 2 , ^ 3 

Discharge in second feet 



Rating Curve for Hill Meter 



180 



UNIVERSITY OF CALIFORNIA — EXPERIMENT STATION 



of flow are made straighter and more nearly parallel, giving more 
uniform action on the vanes of the meter. One disadvantage of the 
Hill meter is its limited range without changing the size of opening, 
but this does not seem to be difficult to overcome. 



Summary of Experiments 



Discharge, 

cubic 

feet 

per 

second 


Length 
of run, 
seconds 


Total 

cubic 

feet 

passing 

meter 


Thou- 
sandths 
acre- 
feet 
on 
counter 


Cubic 

feet 

passed 

per 1/1000 

acre-foot 

on counter 


Loss 

of 
head, 
feet 


Depth 

of 
water 

in 

outlet, 

feet 


Variation 
of actual 

from 

recorded 

discharges, 

cubic feet 

per 

second 


.83 


480 


394 


8.3 


47.5 


.04 


.68 




1.10 


1231 


1361 


31. 


43.9 


.07 


.74 


+ .34 


1.43 


990 


1418 


33. 


43.0 


.12 


.78 


— .56 


1.77 


974 


1742 


40. 


43.2 


.17 


.80 


— .36 


2.10 


460 


967 


22. 


43.9 


.20 


.77 


+ .34 


2.51 


398 


999 


23. 


43.4 


.30 


.83 


— .16 


2,93 


380 


1113 


26. 


42.8 


.41 


.64 


— .76 


3.34 


342 


1141 


26. 


43.9 


.49 


.74 


+ .34 


.74 


1084 


804 


17. 


47.3 


.04 


.57 




.52 


1170 


602 


13. 


46.3 


.03 


.35 




.21 


1974 


408 


8. 


51.0 


.02 


.12 




1.56 


400 


623 


15. 


41.5 


.13 


.34 


—2.06 


1.52 


390 


592 


13. 


45.6 


.12 


.68 


4-2.04 


1.38 


658 


908 


19. 


47.8 


.08 


1.08 


4-4.24 


1.40 


288 


401 


9. 


44.5 


.12 


.72 


+ .94 


1.40 


447 


624 


14. 


44.6 


.13 


.37 


4-1.04 


1.18 


542 


642 


14. 


45.8 


.08 


.67 


4-2.24 


Mean 


of all discharges over 1 


cubic foot per secon 


d, cu. ft. 


per sec. 


+ .5! 


Mean 


in r>er cent ... 












1.3 



STATION PUBLICATIONS AVAILABLE FOR DISTRIBUTION 



REPORTS 

1897. Resistant Vines, their Selection, Adaptation, and Grafting. Appendix to Viticultural 
Report for 1896. 

1902. Report of the Agricultural Experiment Station for 1898-1901. 

1903. Report of the Agricultural Experiment Station for 1901-03. 

1904. Twenty-second Report of the Agricultural Experiment Station for 1903-04. 

1914. Report of the College of Agriculture and the Agricultural Experiment Station, July, 
1913-June, 1914. 

BULLETINS 



No. 
116. The California Vine Hopper. 

168. Observations on Some Vine Diseases 

in Sonoma County. 

169. Tolerance of the Sugar Beet for 

Alkali. 

170. Studies in Grasshopper Control. 
174. A New Wine-Cooling Machine. 

177. A New Method of Making Dry Red 

Wine. 

178. Mosquito Control. 

182. Analysis of Paris Green and Lead 

Arsenate. Proposed Insecticide Law. 

183. The California Tussock-moth. 

184. Report of the Plant Pathologist to 

July 1, 1906. 

185. Report of Progress in Cereal Investi- 

gations. 

186. Oidium of the Vine. 

195. The California Grape Root-worm. 

197. Grape Culture in California; Im- 

proved Methods of Wine-making; 
Yeast from California Grapes. 

198. The Grape Leaf-Hopper. 

203. Report of the Plant Pathologist to 

July 1, 1909. 
207. The Control of the Argentine Ant. 



No. 
208. The Late Blight of Celery. 

211. How to Increase the Yield of Wheat 

in California. 

212. California White Wheats. 

213. The Principles of Wine-making. 

215. The House Fly in its Relation to 

Public Health. 

216. A Progress Report upon Soil and 

Climatic Factors Influencing the 
Composition of Wheat. 

224. The Production of the Lima Bean. 

225. Tolerance of Eucalyptus for Alkali. 
227. Grape Vinegar. 

230. Enological Investigations. 
234. Red Spiders and Mites of Citrus 
Trees. 

240. Commercial Fertilizers. 

241. Vine Pruning in California. Part I. 

242. Humus in California Soils. 

243. The Intradermal Test for Tuber- 

culosis in Cattle and Hogs. 

244. Utilization of Waste Oranges. 

245. Commercial Fertilizers. 

246. Vine Pruning in California, Part II. 

247. Irrigation and Measuring Devices. 



CIRCULARS 



No. 
46. 



65. 
68. 
69. 

70. 

75. 
76. 

70. 
80. 

82. 

83. 
84. 

87. 
88. 



91. 
92. 



98. 



100. 
101. 



102. 



Suggestions for Garden Work in Cali- 
fornia Schools. 

The School Garden in the Course of 
Study. 

The California Insecticide Law. 

The Prevention of Hog Cholera. 

The Extermination of Morning-Glory. 

Observation of the Status of Corn 
Growing in California. 

A New Leakage Gauge. 

Hot Room Callusing. 

List of Insecticide Dealers. 

Boys' and Girls' Clubs. 

The Common Ground Squirrels of 
California. 

Potato Growing Clubs. 

Mushrooms and Toadstools. 

Alfalfa. 

Advantages to the Breeder in Test- 
ing his Pure-Bred Cows for the 
Register of Merit. 

Disinfection on the Farm. 

Infectious Abortion and Sterility in 
Cows. 

Plowing and Cultivating Soils in 
California. 

Pruning Frosted Citrus Trees. 

Codling Moth Control in the Sacra- 
mento Valley. 

The Woolly Aphis. 



No. 

106. Directions for using Anti-Hog-Cholera 

Serum. 

107. Spraying Walnut Trees for Blight 

and Aphis Control. 

108. Grape Juice. 

109. Community or Local Extension Work 

by the High School Agricultural 
Department. 

110. Green Manuring in California. 

111. The Use of Lime and Gypsum on 

California Soils. 

112. The County Farm Adviser. 

113. Announcement of Correspondence 

Courses in Agriculture 

114. Increasing the Duty of Water. 

115. Grafting Vinifera Vineyards. 

116. Silk Worm Experiments. 

117. The Selection and Cost of a Small 

Pumping Plant. 

118. Tho fWntv Farm Bureau. 

119. Winery Directions. 

120. Potato Growing in the San Joaquin 

and Sacramento Deltas of Cali 
fornia. 

121. Some Things the Prospective Settler 

Should Know. 

122. The Management of Strawberry Soils 

in Pajaro Valley. 

123. Fundamental Principles of Co-opera- 

tion in Agriculture. 



